EP4131295A1 - Electromagnetic actuator and circuit breaker using same electromagnetic actuator - Google Patents
Electromagnetic actuator and circuit breaker using same electromagnetic actuator Download PDFInfo
- Publication number
- EP4131295A1 EP4131295A1 EP20928867.9A EP20928867A EP4131295A1 EP 4131295 A1 EP4131295 A1 EP 4131295A1 EP 20928867 A EP20928867 A EP 20928867A EP 4131295 A1 EP4131295 A1 EP 4131295A1
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- European Patent Office
- Prior art keywords
- movable
- core
- fixed
- shaft
- movable core
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
- H01F7/00—Magnets
- H01F7/06—Electromagnets; Actuators including electromagnets
- H01F7/08—Electromagnets; Actuators including electromagnets with armatures
- H01F7/16—Rectilinearly-movable armatures
- H01F7/1607—Armatures entering the winding
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
- H01F7/00—Magnets
- H01F7/06—Electromagnets; Actuators including electromagnets
- H01F7/08—Electromagnets; Actuators including electromagnets with armatures
- H01F7/081—Magnetic constructions
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
- H01F7/00—Magnets
- H01F7/06—Electromagnets; Actuators including electromagnets
- H01F7/08—Electromagnets; Actuators including electromagnets with armatures
- H01F7/13—Electromagnets; Actuators including electromagnets with armatures characterised by pulling-force characteristics
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
- H01H50/00—Details of electromagnetic relays
- H01H50/16—Magnetic circuit arrangements
- H01H50/36—Stationary parts of magnetic circuit, e.g. yoke
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
- H01F7/00—Magnets
- H01F7/06—Electromagnets; Actuators including electromagnets
- H01F7/08—Electromagnets; Actuators including electromagnets with armatures
- H01F7/081—Magnetic constructions
- H01F2007/085—Yoke or polar piece between coil bobbin and armature having a gap, e.g. filled with nonmagnetic material
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
- H01F7/00—Magnets
- H01F7/06—Electromagnets; Actuators including electromagnets
- H01F7/08—Electromagnets; Actuators including electromagnets with armatures
- H01F7/081—Magnetic constructions
- H01F2007/086—Structural details of the armature
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
- H01F7/00—Magnets
- H01F7/06—Electromagnets; Actuators including electromagnets
- H01F7/08—Electromagnets; Actuators including electromagnets with armatures
- H01F7/16—Rectilinearly-movable armatures
- H01F7/1607—Armatures entering the winding
- H01F2007/163—Armatures entering the winding with axial bearing
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
- H01H50/00—Details of electromagnetic relays
- H01H50/16—Magnetic circuit arrangements
- H01H50/18—Movable parts of magnetic circuits, e.g. armature
- H01H50/20—Movable parts of magnetic circuits, e.g. armature movable inside coil and substantially lengthwise with respect to axis thereof; movable coaxially with respect to coil
- H01H50/22—Movable parts of magnetic circuits, e.g. armature movable inside coil and substantially lengthwise with respect to axis thereof; movable coaxially with respect to coil wherein the magnetic circuit is substantially closed
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
- H01H50/00—Details of electromagnetic relays
- H01H50/16—Magnetic circuit arrangements
- H01H50/36—Stationary parts of magnetic circuit, e.g. yoke
- H01H50/42—Auxiliary magnetic circuits, e.g. for maintaining armature in, or returning armature to, position of rest, for damping or accelerating movement
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
- H01H71/00—Details of the protective switches or relays covered by groups H01H73/00 - H01H83/00
- H01H71/10—Operating or release mechanisms
- H01H71/12—Automatic release mechanisms with or without manual release
- H01H71/24—Electromagnetic mechanisms
- H01H71/2454—Electromagnetic mechanisms characterised by the magnetic circuit or active magnetic elements
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
- H01H71/00—Details of the protective switches or relays covered by groups H01H73/00 - H01H83/00
- H01H71/10—Operating or release mechanisms
- H01H71/12—Automatic release mechanisms with or without manual release
- H01H71/24—Electromagnetic mechanisms
- H01H71/2463—Electromagnetic mechanisms with plunger type armatures
Definitions
- the present disclosure relates to an electromagnetic actuator used for a circuit breaker or the like capable of interrupting an electric path, and a circuit breaker using this electromagnetic actuator.
- an electromagnetic actuator is used for operating a contact opening/closing operation.
- the electromagnetic actuator when a current flows through a coil, a magnetic circuit is excited, a movable core inside the electromagnetic actuator is driven in the direction toward a fixed core, and a shaft connected to the movable core moves together with the movable core, thereby operating a contact closing operation of the circuit breaker.
- Patent Document 1 As a technology related to the conventional electromagnetic actuator, for example, there is a technology described in Patent Document.
- a shaft which is an operation shaft for operating a contact closing operation of a circuit breaker is firmly fastened and fixed to a movable core by a set screw for preventing loosening. Accordingly, when a coil is energized, the shaft and the movable core move together.
- a circuit breaker that constantly maintains a contact closed state thereof includes a pushing mechanism in which a movable contact, which is one contact, relatively applies a contact pressure to a fixed contact, which is another contact, during closing. Accordingly, a wipe amount which is the pushing amount of the contact pressure applied to the contact is maintained, and the contacts are brought into a stable contact state during closing.
- Patent Document 1 Japanese Laid-Open Patent Publication No. 9-199320
- circuit breaker is required to be downsized, but there is a problem that the size of the circuit breaker becomes larger when the mechanism for maintaining the wipe amount between the contacts during closing is provided separately from the electromagnetic actuator.
- the present disclosure has been made to solve the above-described problem, and an object of the present disclosure is to obtain an electromagnetic actuator capable of maintaining a wipe amount during closing of a circuit breaker, and a circuit breaker that eliminates the need for providing a mechanism for maintaining a wipe amount, separately from an electromagnetic actuator and can be further downsized.
- An electromagnetic actuator includes: a tubular coil generating a magnetic flux in an axial direction thereof when a current flows therethrough; a movable core installed in a state where the movable core can reciprocate in the axial direction of the coil; a shaft surrounded by the movable core, performing an opening/closing operation between a movable-side contact and a fixed-side contact of a circuit breaker, and movable together with the movable core; a tubular yoke pipe surrounding the coil; a fixed-side lid plate disposed at one end of the yoke pipe in the axial direction of the coil; a movable-side lid plate disposed at another end of the yoke pipe in the axial direction of the coil; a fixed core disposed on an inner circumferential side of the coil from the fixed-side lid plate in a direction toward the movable-side lid plate; and a tubular yoke projection portion projecting on the inner circumferential side of the coil from the movable
- the movable core is disposed in a space on an inner circumferential side of the yoke projection portion, and when the movable core is excited by a current flowing through the coil, the movable core moves together with the shaft from an initial position in a direction toward the fixed core in the axial direction of the coil to bring the movable-side contact and the fixed-side contact into contact with each other to stop movement of the shaft, and then moves relative to the shaft to a position at which the movable core comes into contact with the fixed core in an excitation operation completion state.
- a circuit breaker according to the present disclosure is a circuit breaker in which the electromagnetic actuator according to the present disclosure is used for operating an opening/closing operation between the movable-side contact and the fixed-side contact.
- the movable core can move relative to the shaft toward the fixed core, and a wipe amount at the time of closing of the circuit breaker can be maintained by the operation of the electromagnetic actuator itself.
- FIG. 1 and FIG. 2 schematically illustrate a circuit breaker 110 using an electromagnetic actuator according to Embodiment 1.
- FIG. 1 shows a contact opened state of the circuit breaker 110
- FIG. 2 shows a contact closed state of the circuit breaker 110.
- the circuit breaker 110 is a circuit breaker that constantly maintains a contact closed state thereof by energizing a coil of an electromagnetic actuator. As shown in FIG. 1 and FIG. 2 , the circuit breaker 110 has a movable-side contact 104 and a fixed-side contact 105 which are a pair of contacts, an electromagnetic actuator 100 provided with a shaft 8 for operating a contact opening/closing operation, and an arc extinguishing chamber 108.
- a movable conductor 103, a flexible conductor 106, a lower conductor 101, and an opening spring 107 are provided on the movable-side contact 104 side.
- An upper conductor 102 is provided on the fixed-side contact 105 side.
- the fixed-side contact 105 which is one of the pair of contacts, is joined to one end portion of the upper conductor 102 and electrically connected to the upper conductor 102.
- the movable-side contact 104 which is the other of the pair of contacts, is joined to one end portion of the movable conductor 103 at a position facing the fixed-side contact 105. Another end portion of the movable conductor 103 is connected to the lower conductor 101 by the flexible conductor 106.
- the movable-side contact 104 is electrically connected to the lower conductor 101 via the movable conductor 103 and the flexible conductor 106.
- the flexible conductor 106 is biased by the shaft 8 of the electromagnetic actuator 100 so as to open and close the movable-side contact 104 and the fixed-side contact 105.
- the lower conductor 101, the upper conductor 102, the movable conductor 103, the movable-side contact 104, the fixed-side contact 105, and the flexible conductor 106 are composed of conductors.
- the movable-side contact 104 and the fixed-side contact 105 are energized via the lower conductor 101 and the upper conductor 102, respectively.
- the movable-side contact 104 becomes connected to the fixed-side contact 105 by the movable conductor 103 moving toward the upper conductor 102.
- the movable-side contact 104 becomes disconnected from the fixed-side contact 105 by the movable conductor 103 moving in the direction away from the upper conductor 102.
- a state where the movable-side contact 104 and the fixed-side contact 105 are connected to each other is a contact closed state, and a state where the movable-side contact 104 and the fixed-side contact 105 are separated from each other is a contact opened state.
- the movable-side contact 104 and the fixed-side contact 105 are made to be connected to each other by an excitation operation of the electromagnetic actuator 100, to bring about the contact closed state shown in FIG. 2 .
- the lower conductor 101 and the upper conductor 102 are energized via the movable-side contact 104 and the fixed-side contact 105.
- the movable-side contact 104 and the fixed-side contact 105 become separated from each other by a demagnetization operation of the electromagnetic actuator 100, to bring about the contact opened state shown in FIG. 1 .
- the energization of the lower conductor 101 and the upper conductor 102 is stopped.
- the opening spring 107 is connected to the movable conductor 103 and is provided so as to perform contact opening on the movable-side contact 104 side of the movable conductor 103.
- the opening spring 107 elastically stores a force that separates the movable-side contact 104 from the fixed-side contact 105.
- Contact opening and contact closing which are a contact opening operation and a contact closing operation are performed by the operation of the electromagnetic actuator 100. When the electromagnetic actuator 100 is driven for contact closing, contact closing is performed against the stored force of the opening spring 107.
- the shaft 8 is disposed so as to pass through the axis center of the electromagnetic actuator 100.
- the movable conductor 103 is connected to the electromagnetic actuator 100 via the shaft 8.
- the electromagnetic actuator 100 operates the opening/closing operation between the contacts of the circuit breaker 110.
- the electromagnetic actuator 100 moves the movable conductor 103 via the shaft 8 to control the connection between the movable-side contact 104 and the fixed-side contact 105.
- FIG. 3 corresponds to the opened state of the circuit breaker 110 shown in FIG. 1 , and is a cross-sectional view showing a demagnetized state of the electromagnetic actuator 100 according to Embodiment 1.
- the demagnetized state of the electromagnetic actuator 100 shown in FIG. 3 is a state where a movable core 2 is located at an initial position.
- FIG. 4 corresponds to the closed state of the circuit breaker 110 shown in FIG. 2 , and is a cross-sectional view showing an excitation operation completion state of the electromagnetic actuator 100 according to Embodiment 1.
- the excitation operation completion state of the electromagnetic actuator 100 shown in FIG. 4 is a state where the movable core 2 is in contact with a fixed core 3.
- the electromagnetic actuator 100 has a tubular coil 1 which generates a magnetic flux in an axial direction thereof when a current flows therethrough, the movable core 2 which is disposed in the axial direction of the coil 1 and is installed in a state where the movable core 2 can reciprocate in the axial direction of the coil 1, the shaft 8 which is surrounded by the movable core 2 and is movable together with the movable core 2, a tubular yoke pipe 4 which surrounds the coil 1, a fixed-side lid plate 5 which is disposed at one end of the yoke pipe 4 in the axial direction of the coil 1, a movable-side lid plate 6 which is disposed at the other end of the yoke pipe 4 in the axial direction of the coil 1, the fixed core 3 which is disposed on the inner circumferential side of the coil 1 from the fixed-side lid plate 5 in the direction toward the movable-side lid plate 6, and a tubular yoke projection portion 7 which projects on the inner circumferential side of the coil 1 from the
- the yoke pipe 4 is disposed between the fixed-side lid plate 5 and the movable-side lid plate 6, and the fixed-side lid plate 5 and the movable-side lid plate 6 are disposed so as to face each other.
- the fixed core 3 faces the yoke projection portion 7 and the movable core 2 which is surrounded by the yoke projection portion 7.
- Components including the yoke pipe 4, the fixed-side lid plate 5, the movable-side lid plate 6, the fixed core 3, and the yoke projection portion 7 are integrated with a step, and are made of a magnetic material.
- a typical magnetic material is, for example, iron.
- a magnetic circuit is excited together with the movable core 2 by energizing the coil 1.
- the coil 1 is housed in a tubular space which is formed by the yoke pipe 4, the fixed-side lid plate 5, the movable-side lid plate 6, the fixed core 3, and the yoke projection portion 7.
- the coil 1 has a tubular shape that surrounds the movable core 2, the yoke projection portion 7, and the fixed core 3.
- the movable core 2 is disposed on the inner circumferential side of the yoke projection portion 7 so as to face the fixed core 3, and is installed in a state where the movable core 2 can reciprocate relative to the fixed core 3 in the axial direction of the coil 1. Specifically, when a current flows through the coil 1, the movable core 2 is driven so as to move toward the fixed core 3 in the axial direction of the coil 1. In this case, the movable core 2 moves from the initial position which is a position in the demagnetized state of the electromagnetic actuator 100 in which the contact opened state of the circuit breaker 110 shown in FIG. 3 is maintained, to a position at which the movable core 2 comes into contact with the fixed core 3 and which is a position in the excitation operation completion state of the electromagnetic actuator 100 in which the closed state of the circuit breaker 110 shown in FIG. 4 is maintained.
- the length of the movable core 2 is longer than 1/2 of the length of the yoke pipe 4.
- a movable core end surface 2a of the movable core 2 is located on the fixed core 3 side with respect to the center position of the coil 1 in the axial direction.
- the facing area between the movable core 2 and the yoke projection portion 7 in the axial direction becomes larger.
- the magnetic resistance of the magnetic circuit is reduced by increasing the magnetic path cross-sectional area corresponding to the facing area.
- the attractive force acting on the movable core 2 in an excitation maintained state can be further improved. Accordingly, the holding force between the main contacts in the closed state of the circuit breaker 110 can be improved.
- the shaft 8 is surrounded by the movable core 2 and is disposed in the axial direction of the coil 1.
- the shaft 8 is made of a non-magnetic material.
- the shaft 8 penetrates the fixed-side lid plate 5, the fixed core 3, and the movable-side lid plate 6.
- the shaft 8 has a first shaft end portion 8a which is one end portion penetrating the fixed-side lid plate 5, and a second shaft end portion 8b which is another end portion penetrating the movable-side lid plate 6.
- the first shaft end portion 8a extends to the movable conductor 103 and is connected to the movable conductor 103.
- the second shaft end portion 8b is formed such that the outer diameter thereof is larger than that of a portion, of the shaft 8, which is inserted into the movable core 2.
- a shaft protrusion portion 8c and a shaft step portion 8d are formed on the shaft 8.
- the shaft protrusion portion 8c faces the fixed core 3, and the shaft step portion 8d is located at an end portion on the fixed-side lid plate 5 side of the movable core 2 so as to be adjacent to the shaft protrusion portion 8c.
- the shaft protrusion portion 8c and the shaft step portion 8d are formed such that the outer diameters thereof are larger than that of the portion, of the shaft 8, which is inserted into the movable core 2.
- the first movable core bearing 13 is provided on the shaft step portion 8d of the shaft 8 at an end portion position on the fixed-side lid plate 5 side of the movable core 2.
- the movable core 2 is supported by the first movable core bearing 13 so as to be movable relative to the shaft 8.
- the first movable core bearing 13 By disposing the first movable core bearing 13 on the shaft 8 which is a non-magnetic component, the movable core 2 can be formed without decreasing the cross-sectional area thereof, and the attractive force can be ensured.
- the second movable core bearing 14 is provided at an end portion position on the movable-side lid plate 6 side of the movable core 2.
- the second movable core bearing 14 supports the movable core 2 so as to be movable together with the movable core 2 relative to the shaft 8.
- a contact-pressure spring 9 is disposed between the movable core 2 and the shaft 8.
- the shaft 8 and the movable core 2 are connected via the contact-pressure spring 9.
- the contact-pressure spring 9 is provided in the movable core 2, and is located between the first movable core bearing 13 and the second movable core bearing 14 in the axial direction.
- the electromagnetic actuator 100 is made compact. By increasing the length of the movable core 2, it is possible to increase the length of the contact-pressure spring 9.
- the contact-pressure spring 9 is compressed to store a force in a direction in which the movable core 2 is separated from the fixed core 3.
- a return spring 10 is disposed between the shaft protrusion portion 8c and the fixed core 3.
- the shaft 8 and the fixed core 3 are connected via the return spring 10.
- the return spring 10 has a tubular shape that surrounds the shaft 8 and is surrounded by the fixed core 3. When the shaft 8 moves together with the movable core 2 in the direction toward the fixed core 3, the return spring 10 is compressed to store a force in a direction in which the contacts of the circuit breaker are separated from each other.
- shaft bearings which support movement of the shaft 8 are disposed at the fixed-side lid plate 5 and the movable-side lid plate 6, respectively, in the axial direction.
- a first shaft bearing 11 is provided at a center portion of the fixed-side lid plate 5, and a second shaft bearing 12 is provided at a center portion of the movable-side lid plate 6.
- the first shaft bearing 11 is disposed between the fixed-side lid plate 5 and the first shaft end portion 8a of the shaft 8 which penetrates the fixed-side lid plate 5.
- the second shaft bearing 12 is disposed between the movable-side lid plate 6 and the second shaft end portion 8b of the shaft 8 which penetrates the movable-side lid plate 6.
- the shaft 8 can move in the axial direction of the coil 1 while being supported by the first shaft bearing 11 and the second shaft bearing 12.
- the movable core 2 and the fixed core 3 each have a tubular shape that surrounds the shaft 8.
- the movable core 2 and the fixed core 3 In a direction perpendicular to the axial direction of the coil 1, the movable core 2 and the fixed core 3 have the movable core end surface 2a and a fixed core end surface 3a which face each other.
- the movable core end surface 2a is an annular surface facing the fixed core end surface 3a
- the fixed core end surface 3a is an annular surface facing the movable core end surface 2a.
- a gap s1 having a predetermined distance is provided at the facing position between the movable core end surface 2a and the fixed core end surface 3a.
- the movable core 2 is excited and driven in the axial direction toward the fixed core 3, the gap s1 becomes smaller as the movable core 2 moves, and in the excitation operation completion state, the movable core end surface 2a comes into contact with the fixed core end surface 3a, so that the gap s1 becomes zero.
- the fixed core end surface 3a is located on the fixed-side lid plate 5 side with respect to the center in the axial direction of the coil 1.
- a surface at which the movable core end surface 2a of the movable core 2 comes into contact with the fixed core end surface 3a of the fixed core 3 in the excitation operation completion state in which the movable core 2 has been excited and driven in the axial direction toward the fixed core 3, as shown in FIG. 4 is referred to as a contact surface 16.
- the position of the contact surface 16 is the same as the position of the fixed core end surface 3a, and the contact surface 16 between the movable core 2 and the fixed core 3 in the excitation operation completion state is located on the movable core 2 moving direction side with respect to the center in the axial direction of the coil 1. That is, the contact surface 16 is located on the fixed-side lid plate 5 side with respect to the center in the axial direction of the coil 1.
- a fixed core recess 3b which faces the shaft protrusion portion 8c of the shaft 8 and is recessed so as to house the shaft protrusion portion 8c and the return spring 10 is formed at a center portion in the axial direction of the fixed core end surface 3a.
- a fixed core step portion 3c is provided so as to be stepped on an inner wall surface of the fixed core recess 3b and face the shaft protrusion portion.
- the shaft protrusion portion 8c is surrounded by the fixed core recess 3b so as to be housed in the fixed core recess 3b, and contacts the fixed core 3 via the return spring 10.
- the yoke projection portion 7 has a yoke main projection portion 7a which is disposed on the movable-side lid plate 6 side, and a yoke narrow projection portion 7b which extends from the yoke main projection portion 7a toward the fixed-side lid plate 5 side.
- the yoke projection portion 7 faces the fixed core 3, and is disposed such that the yoke narrow projection portion 7b extends in the direction toward the fixed core 3.
- a yoke projection portion distal end surface 7c which is an end surface, of the yoke projection portion 7, facing the fixed core 3 projects so as to be closer to the fixed core 3 than the movable core end surface 2a is at the initial position.
- a gap g1 having a predetermined distance is provided at the facing position between the yoke projection portion distal end surface 7c and the fixed core end surface 3a.
- the gap g1 is smaller than the gap s1 between the fixed core end surface 3a and the movable core end surface 2a at the initial position.
- the inner diameter of the yoke main projection portion 7a and the inner diameter of the yoke narrow projection portion 7b are equal to each other, and the outer diameter of the yoke main projection portion 7a is larger than the outer diameter of the yoke narrow projection portion 7b.
- the yoke main projection portion 7a and the yoke narrow projection portion 7b may be integrally formed or may be formed as separate components. Both the yoke main projection portion 7a and the yoke narrow projection portion 7b have a yoke projection portion inner wall surface 7d which is an inner wall surface of the yoke projection portion 7.
- the characteristics of the attractive force applied to the movable core 2 can be adjusted by adjusting the configuration of the yoke projection portion 7 such as the outer diameter difference between the yoke main projection portion 7a and the yoke narrow projection portion 7b and the width of the yoke narrow projection portion 7b.
- the yoke projection portion inner wall surface 7d faces a movable core outer wall surface 2b, which is an outer wall surface of the movable core 2, so as to surround the movable core 2.
- the yoke projection portion 7 has the yoke narrow projection portion 7b which extends from the yoke main projection portion 7a, and by increasing the length of the movable core 2, the facing area between the movable core 2 and the yoke projection portion 7 becomes larger, that is, the facing area between the movable core outer wall surface 2b and the yoke projection portion inner wall surface 7d becomes larger.
- the magnetic circuit composed of the movable core 2, the fixed core 3, the fixed-side lid plate 5, the yoke pipe 4, the movable-side lid plate 6, and the yoke projection portion 7 is excited, a magnetic attractive force acts on the movable core 2, and the movable core 2 is driven in the direction toward the fixed core 3.
- the movable core 2 shown in FIG. 3 is driven from the initial position to the position at which the movable core 2 comes into contact with the fixed core 3 and which is a position in the excitation operation completion state shown in FIG. 4 .
- the circuit breaker 110 is brought into the closed state shown in FIG. 2 from the opened state shown in FIG. 1 .
- the contact-pressure spring 9 which connects the movable core 2 and the shaft 8 is pressed by the moving movable core 2, so that the shaft 8 moves together with the movable core 2 from the movable-side lid plate 6 side toward the fixed-side lid plate 5 side.
- the movable conductor 103 which is connected to the shaft 8 moves in the left direction on the drawing sheet in FIG. 1 so as to bring the movable-side contact 104 and the fixed-side contact 105 into contact with each other.
- the return spring 10 between the shaft protrusion portion 8c and the fixed core 3 is compressed to store a force.
- the shaft 8 stops. After the movement of the shaft 8 is stopped, the movable core 2 is further driven in the direction toward the fixed core 3 relative to the shaft 8 by the magnetic attractive force. Then, the movable core end surface 2a of the movable core 2 and the fixed core end surface 3a of the fixed core 3 come into contact with each other to complete the excitation operation, and the circuit breaker is brought into the closed state.
- the movable core 2 moves relative to the shaft 8, thereby further applying a contact pressure to the movable-side contact 104 and the fixed-side contact 105 via the shaft 8. Accordingly, a wipe amount at the time of closing can be maintained by the operation of the electromagnetic actuator itself.
- the return spring 10 is compressed and the shaft 8 contacts the fixed core 3 via the return spring 10.
- the shaft protrusion portion 8c is surrounded by the fixed core recess 3b so as to be housed in the fixed core recess 3b, and does not completely contact the fixed core step portion 3c in the fixed core recess 3b, so that there is a gap 16a therebetween.
- the movable core 2 can apply a contact pressure between the contacts via the shaft 8.
- the shaft protrusion portion 8c contacts the fixed core step portion 3c via the return spring 10 such that the stored force of the contact-pressure spring 9 remains. Since the gap 16a exists, the stored force of the contact-pressure spring 9 can be released when the magnetic circuit is demagnetized. In the electromagnetic actuator, an attractive force may act between the movable core and the fixed core due to the influence of the residual magnetic field, and the movable core 2 can be separated from the fixed core 3 by using the stored force of the contact-pressure spring 9. Since the stored force of the contact-pressure spring 9 can be used, the size of the return spring 10 which is provided on the fixed core 3 side can be reduced, so that the return spring 10 can be downsized.
- the magnetic circuit When the magnetic circuit is demagnetized by stopping the energization of the coil 1, the magnetic attractive force disappears, the contact-pressure spring 9 extends, and the movable core 2 moves in a direction opposite to a direction in which the fixed core 3 is disposed.
- the second shaft end portion 8b is brought into contact with the movable core 2, and the shaft 8 moves together with the movable core.
- the return spring 10 extends, and the movable conductor 103 which is connected to the shaft 8 moves in the right direction on the drawing sheet in FIG. 1 so as to separate the movable-side contact 104 and the fixed-side contact 105 from each other, so that the contacts are completely separated with the stored force of the opening spring 107.
- the movable core 2 returns to the initial position. Accordingly, the electromagnetic actuator 100 is brought into the demagnetized state, and the circuit breaker 110 is brought into the opened state shown in FIG. 1 .
- FIG. 5 illustrates the magnetic circuit at the initial position of the movable core 2 of the electromagnetic actuator 100 according to Embodiment 1.
- a magnetic flux 24 in the axial direction which is generated in the magnetic circuit by energizing the coil 1 has a magnetic flux 24a which passes through the movable core 2, and a magnetic flux 24b which passes through the yoke projection portion 7.
- a part of the magnetic flux 24 in the axial direction flows from the yoke main projection portion 7a of the yoke projection portion 7 through the yoke narrow projection portion 7b to the fixed core 3, and the magnetic flux flowing through the movable core 2 becomes smaller.
- the driving force applied to the movable core 2 is reduced, so that it is possible to slow down the excitation operation of the electromagnetic actuator 100. Accordingly, it is possible to close the contacts of the circuit breaker 110 at low speed.
- the magnetic flux passes through the movable core 2 and the fixed core 3 from the yoke projection portion 7.
- the gap s1 between the movable core end surface 2a and the fixed core end surface 3a becomes smaller.
- the contact surface 16 between the movable core 2 and the fixed core 3 is located on the movable core 2 moving direction side with respect to the center in the axial direction of the coil 1, and by increasing the length of the movable core 2 and extending the yoke narrow projection portion 7b of the yoke projection portion 7 in the direction toward the fixed core 3, the facing area between the yoke projection portion 7 and the movable core 2 in the direction perpendicular to the axial direction becomes larger, so that the attractive force in the excitation maintained state can be further improved.
- the movable core can move relative to the shaft toward the fixed core, and a wipe amount at the time of closing of the circuit breaker can be maintained by the operation of the electromagnetic actuator itself.
- the electromagnetic actuator according to Embodiment 1 since the contact surface between the movable core and the fixed core is located on the movable core moving direction side with respect to the center position of the coil in the axial direction of the coil, the distance between the contact surface and the initial position can be ensured. Even when the length in the axial direction of the movable core is increased, the movable core can be formed without projecting outward from the movable-side lid plate at the initial position, so that it is possible to reduce the external dimensions of the electromagnetic actuator. Accordingly, the circuit breaker using the electromagnetic actuator can be downsized.
- the electromagnetic actuator according to Embodiment 1 owing to the configuration in which the yoke narrow projection portion is provided in the yoke projection portion, the effects of slowing down the excitation operation and improving the attractive force in the excitation maintained state are achieved. Accordingly, the contacts of the circuit breaker using the electromagnetic actuator can be closed at low speed, and the holding force between the contacts in the closed state can be improved.
- FIGS. 6 and 7 are cross-sectional views of an electromagnetic actuator 200 according to Embodiment 2 of the present disclosure.
- FIG. 6 is a cross-sectional view showing a demagnetized state of the electromagnetic actuator 200 according to Embodiment 2, corresponding to the opened state of the circuit breaker shown in FIG. 1 .
- FIG. 6 is a cross-sectional view showing a state where a movable core 2 is at an initial position in the demagnetized state of the electromagnetic actuator 200.
- FIG. 7 is a cross-sectional view showing an excitation operation completion state of the electromagnetic actuator 200 according to Embodiment 2, corresponding to the closed state of the circuit breaker shown in FIG. 2 .
- the excitation operation completion state of the electromagnetic actuator 200 shown in FIG. 7 is a state where the movable core 2 is in contact with a fixed core 3.
- the electromagnetic actuator 200 serves to bias the movable contact of the circuit breaker in the closing direction and is used for operating an opening/closing operation between the contacts.
- Embodiment 2 the same components as those in Embodiment 1 of the present disclosure are denoted by the same reference characters, and the description of the same or corresponding parts is omitted.
- the differences of the electromagnetic actuator 200 according to Embodiment 2 from Embodiment 1 will be described with reference to the drawings.
- the electromagnetic actuator 200 has a tubular coil 1 which generates a magnetic flux in an axial direction thereof when a current flows therethrough, the movable core 2 which is disposed in the axial direction of the coil 1 and is installed in a state where the movable core 2 can reciprocate in the axial direction of the coil 1, a shaft 8 which is surrounded by the movable core 2 and is movable together with the movable core 2, a tubular yoke pipe 4 which surrounds the coil 1, a fixed-side lid plate 5 which is disposed at one end of the yoke pipe 4 in the axial direction of the coil 1, a movable-side lid plate 6 which is disposed at the other end of the yoke pipe 4 in the axial direction of the coil 1, the fixed core 23 which is disposed on the inner circumferential side of the coil 1 from the fixed-side lid plate 5 in the direction toward the movable-side lid plate 6, and a tubular yoke projection portion 27 which projects on the
- Components including the yoke pipe 4, the fixed-side lid plate 5, the movable-side lid plate 6, the fixed core 23, and the yoke projection portion 27 are integrated with a step, and are made of a magnetic material.
- a typical magnetic material is, for example, iron.
- a magnetic circuit is excited together with the movable core 2 by energizing the coil 1.
- the configurations of the fixed core 23 and the yoke projection portion 27 are different from the configurations of the fixed core 3 and the yoke projection portion 7 of Embodiment 1.
- the configuration other than the fixed core 23 and the tubular yoke projection portion 27 is the same as in Embodiment 1. The same advantageous effects are achieved.
- the tubular yoke projection portion 27 projects from the movable-side lid plate 6 in the direction toward the fixed-side lid plate 5 so as to surround a part of the movable core 2 at the initial position, and both the outer diameter and the inner diameter of the tubular yoke projection portion 27 are uniform.
- the tubular yoke projection portion 27 has a yoke projection portion distal end surface 27a which is an annular end surface facing the fixed core 23, and a yoke projection portion inner wall surface 27b which faces a movable core outer wall surface 2b which is an outer wall surface of the movable core 2.
- the fixed core 23 has a fixed core base portion 23a which is disposed on the fixed-side lid plate 5 side, and a fixed core narrow projection portion 23b which extends from the fixed core base portion 23a in the direction toward the movable-side lid plate 6.
- the fixed core base portion 23a and the fixed core narrow projection portion 23b may be integrally formed or may be formed as separate components.
- the fixed core base portion 23a is disposed so as to face the movable core 2 and the tubular yoke projection portion 27 which surrounds the movable core 2.
- the fixed core base portion 23a has a fixed core end surface 23c which is an end surface facing the movable core 2.
- the fixed core end surface 23c is an annular surface facing a movable core end surface 2a, and is located on the fixed-side lid plate 5 side with respect to the center in the axial direction of the coil 1.
- a gap s2 having a predetermined distance is provided at the facing position between the movable core end surface 2a and the fixed core end surface 23c.
- the movable core 2 is excited and driven in the axial direction toward the fixed core 23, the gap s2 becomes smaller as the movable core 2 moves, and in the excitation operation completion state, the movable core end surface 2a comes into contact with the fixed core end surface 23c, so that the gap s2 becomes zero.
- a surface at which the movable core end surface 2a of the movable core 2 comes into contact with the fixed core end surface 23c of the fixed core 23 in the excitation operation completion state as shown in FIG. 7 is referred to as a contact surface 26.
- the position of the contact surface 26 is the same as the position of the fixed core end surface 23c, and is located on the movable core 2 moving direction side with respect to the center position in the axial direction of the coil 1. That is, the contact surface 26 is located on the fixed-side lid plate 5 side with respect to the center in the axial direction of the coil 1.
- a fixed core recess 23f which faces a shaft protrusion portion 8c of the shaft 8 and is recessed so as to house the shaft protrusion portion 8c and a return spring 10 is formed at a center portion in the axial direction of the fixed core end surface 23c.
- a fixed core step portion 23g is provided so as to be stepped on an inner wall surface of the fixed core recess 23f and face the shaft protrusion portion.
- the shaft protrusion portion 8c is surrounded by the fixed core step portion 23g so as to be housed in the fixed core step portion 23g.
- the fixed core narrow projection portion 23b extends in the direction toward the movable core 2, and has a tubular shape that surrounds a movable core distal end portion 2c which is a distal end portion of the movable core 2 in a direction in which the movable core 2 moves toward the fixed core base portion 23a.
- the fixed core narrow projection portion 23b has a fixed core distal end surface 23d which is an annular end surface facing the tubular yoke projection portion 27, and a fixed core inner wall surface 23e which is an inner wall surface facing the movable core outer wall surface 2b.
- the movable core distal end portion 2c is surrounded by the fixed core narrow projection portion 23b, and a portion on the movable-side lid plate 6 side other than the movable core distal end portion 2c is surrounded by the tubular yoke projection portion 27.
- the fixed core distal end surface 23d projects so as to be closer to the tubular yoke projection portion 27 than the position of the movable core end surface 2a is at the initial position.
- a gap g2 having a predetermined distance is provided at the facing position between the yoke projection portion distal end surface 27a and the fixed core distal end surface 23d. The gap g2 is smaller than the gap s2 at the initial position.
- the magnetic circuit composed of the movable core 2, the fixed core 23, the fixed-side lid plate 5, the yoke pipe 4, the movable-side lid plate 6, and the yoke projection portion 27 is excited, a magnetic attractive force acts on the movable core 2, and the movable core 2 is driven in the direction toward the fixed core 23.
- the movable core 2 shown in FIG. 6 is driven from the initial position to the position at which the movable core 2 comes into contact with the fixed core 23 and which is a position in the excitation operation completion state shown in FIG. 7 .
- the circuit breaker 110 is brought into the closed state shown in FIG. 2 from the opened state shown in FIG. 1 .
- the contact-pressure spring 9 which connects the movable core 2 and the shaft 8 is pressed by the moving movable core 2, so that the shaft 8 moves together with the movable core 2 in the axial direction from the movable-side lid plate 6 side toward the fixed-side lid plate 5 side.
- the contacts of the circuit breaker come into contact with each other via a movable conductor connected to the shaft 8.
- the shaft 8 stops.
- the movable core 2 is driven by the magnetic attractive force so as to further move relative to the shaft 8 to the position at which the movable core 2 comes into contact with the fixed core 23.
- the movable core end surface 2a of the movable core 2 and the fixed core end surface 23c of the fixed core 23 come into contact with each other to complete the excitation operation, and the circuit breaker is brought into the closed state.
- the movable core 2 moves relative to the shaft 8, thereby further applying a contact pressure to the contacts of the circuit breaker via the shaft 8. Accordingly, a wipe amount at the time of closing can be maintained by the operation of the electromagnetic actuator itself.
- the return spring 10 is compressed and the shaft 8 contacts the fixed core 23 via the return spring 10.
- the shaft protrusion portion 8c is surrounded by the fixed core recess 23f so as to be housed in the fixed core recess 23f, and does not completely contact the fixed core step portion 23g in the fixed core recess 23f, so that there is a gap 26a therebetween.
- the movable core 2 can apply a contact pressure between the contacts via the shaft 8.
- the shaft protrusion portion 8c contacts the fixed core step portion 23g via the return spring 10 such that the stored force of the contact-pressure spring 9 remains. Since the gap 26a exists, the stored force of the contact-pressure spring 9 can be released when the magnetic circuit is demagnetized. In the electromagnetic actuator, an attractive force may act between the movable core and the fixed core due to the influence of the residual magnetic field, and the movable core 2 can be separated from the fixed core 23 by using the stored force of the contact-pressure spring 9. Since the stored force of the contact-pressure spring 9 can be used, the size of the return spring 10 which is provided on the fixed core 23 side can be reduced, so that the return spring 10 can be downsized.
- the magnetic circuit When the magnetic circuit is demagnetized by stopping the energization of the coil 1, the magnetic attractive force disappears, the contact-pressure spring 9 extends, and the movable core 2 moves in a direction opposite to a direction in which the fixed core 23 is disposed.
- the movable core 2 is brought into contact with the second shaft end portion 8b, and the shaft 8 moves together with the movable core.
- the return spring 10 extends, and the movable conductor 103 which is connected to the shaft 8 moves in a direction in which the movable-side contact 104 and the fixed-side contact 105 are separated from each other, so that the contacts are completely separated with the stored force of an opening spring 107.
- the movable core 2 returns to the initial position. Accordingly, the electromagnetic actuator 200 is brought into the demagnetized state, and the circuit breaker is brought into the opened state.
- FIG. 8 illustrates the magnetic circuit at the initial position of the movable core 2 of the electromagnetic actuator 200 according to Embodiment 2.
- a magnetic flux 28 in the axial direction which is generated in the magnetic circuit by energizing the coil 1 has a magnetic flux 28a which passes through the movable core 2, and a magnetic flux 28b which passes through the fixed core narrow projection portion 23b from the tubular yoke projection portion 27.
- a part of the magnetic flux 28 in the axial direction flows from the tubular yoke projection portion 27 through the fixed core narrow projection portion 23b to the fixed core 23, and the magnetic flux flowing through the movable core 2 becomes smaller.
- the driving force applied to the movable core 2 is reduced, so that it is possible to slow down the excitation operation of the electromagnetic actuator 200. Accordingly, it is possible to close the contacts of the circuit breaker at low speed.
- the movable core can move relative to the shaft toward the fixed core, and a wipe amount at the time of closing of the circuit breaker can be maintained by the operation of the electromagnetic actuator itself.
- the electromagnetic actuator according to Embodiment 2 since the contact surface between the movable core and the fixed core is located on the movable core moving direction side with respect to the center position of the coil in the axial direction of the coil, the distance between the contact surface and the initial position can be ensured. Even when the length in the axial direction of the movable core is increased, the movable core can be formed without projecting outward from the movable-side lid plate at the initial position, so that it is possible to reduce the external dimensions of the electromagnetic actuator. Accordingly, the circuit breaker using the electromagnetic actuator can be downsized.
- the electromagnetic actuator according to Embodiment 2 owing to the configuration of the fixed core provided with the fixed core narrow projection portion, the slowdown of the excitation operation can be improved. Accordingly, it is possible to close the contacts of the circuit breaker, which uses this electromagnetic actuator, at low speed.
- FIGS. 9 and 10 are cross-sectional views of an electromagnetic actuator 300 according to Embodiment 3 of the present disclosure.
- FIG. 9 corresponds to the opened state of the circuit breaker 110 shown in FIG. 1 , and is a cross-sectional view showing a demagnetized state of the electromagnetic actuator 300 according to Embodiment 3.
- the demagnetized state of the electromagnetic actuator 300 shown in FIG. 9 is a state where a movable core 2 of the electromagnetic actuator 300 is located at an initial position.
- FIG. 10 corresponds to the closed state of the circuit breaker 110 shown in FIG. 2 , and is a cross-sectional view showing an excitation operation completion state of the electromagnetic actuator 300 according to Embodiment 3.
- the excitation operation completion state of the electromagnetic actuator 300 shown in FIG. 10 is a state where the movable core 2 is in contact with a fixed core 3.
- the electromagnetic actuator 300 serves to bias the movable contact of the circuit breaker in the closing direction and is used for operating an opening/closing operation between the contacts.
- Embodiment 3 the same components as those in Embodiment 1 of the present disclosure are denoted by the same reference characters, and the description of the same or corresponding parts is omitted.
- the differences of the electromagnetic actuator 300 according to Embodiment 3 from Embodiment 1 will be described with reference to the drawings.
- the electromagnetic actuator 300 has a tubular coil 1 which generates a magnetic flux in an axial direction thereof when a current flows therethrough, the movable core 2 in which a tubular space for housing the coil is formed and which is disposed in the axial direction of the coil 1 and is installed in a state where the movable core 2 can reciprocate in the axial direction of the coil 1, a shaft 8 which is surrounded by the movable core 2 and is movable together with the movable core 2, a tubular yoke pipe 4 which surrounds the coil 1, a fixed-side lid plate 5 which is disposed at one end of the yoke pipe 4 in the axial direction of the coil 1, a movable-side lid plate 36 which is disposed at the other end of the yoke pipe 4 in the axial direction of the coil 1, the fixed core 3 which is disposed on the inner circumferential side of the coil 1 from the fixed-side lid plate 5 in the direction toward the movable-side lid plate 36, and
- Components including the yoke pipe 4, the fixed-side lid plate 5, the movable-side lid plate 36, the fixed core 3, and the yoke projection portion 7 are integrated with a step, and are made of a magnetic material.
- a typical magnetic material is, for example, iron.
- a magnetic circuit is excited together with the movable core 2 by energizing the coil 1.
- the configuration of the movable-side lid plate 36 is different from the configuration of the movable-side lid plate 6 of Embodiment 1.
- an air outlet 33 is provided at a portion surrounded by the yoke projection portion 7, so as to penetrate the movable-side lid plate 36.
- an airtight bearing which supports movement of the movable core 2 relative to the yoke projection portion 7 and blocks outflow of air is provided between the movable core 2 and the yoke projection portion 7.
- the airtight bearing is movable together with the movable core 2 and is disposed such that the air inside the electromagnetic actuator does not leak from between the movable core 2 and the yoke projection portion 7.
- a plurality of airtight bearings can be provided between the movable core 2 and the yoke projection portion 7, and the airtightness and the holding stability of the movable core 2 can be improved.
- a third movable core bearing 31 and a fourth movable core bearing 32 which are airtight bearings, are provided at both end portions of the movable core 2, respectively.
- the third movable core bearing 31 and the fourth movable core bearing 32 have a hermetically sealed configuration such that the air inside the electromagnetic actuator does not leak from between the movable core 2 and the yoke projection portion 7, and support the movable core 2 so as to be movable together with the movable core 2 relative to the yoke projection portion 7.
- a spring pressing plate 34 is provided between the movable core 2 and a contact-pressure spring 9.
- the contact-pressure spring 9 is pressed by the moving movable core 2 via the spring pressing plate 34, and the shaft 8 moves together with the movable core 2 in the axial direction from the movable-side lid plate 6 side toward the fixed-side lid plate 5 side.
- the spring pressing plate 34 is also in contact with the movable core 2 and the shaft 8, and also has a function of closing the gap between the movable core 2 and the shaft 8 such that the air inside the movable core 2 does not leak.
- the configuration other than the configuration of the movable-side lid plate 36 and the airtight bearings between the movable core 2 and the yoke projection portion 7 is the same as in Embodiment 1. The same advantageous effects are achieved.
- Embodiment 3 As for the operation of the electromagnetic actuator 300 according to Embodiment 3, the difference from Embodiment 1 will be described.
- the electromagnetic actuator 300 is the same as in Embodiment 1, except that in the electromagnetic actuator 300, by stopping the energization of the coil 1, the magnetic circuit is demagnetized, and when the movable core 2 moves from the position at which the movable core 2 comes into contact with the fixed core 3, to the initial position, the movable core 2 discharges air through the air outlet 33.
- the magnetic circuit When the magnetic circuit is demagnetized by stopping the energization of the coil 1, the magnetic attractive force disappears, the contact-pressure spring 9 extends, and the movable core 2 moves in a direction opposite to a direction in which the fixed core 3 is disposed.
- the movable core 2 is brought into contact with the second shaft end portion 8b, and the shaft 8 moves together with the movable core 2.
- the return spring 10 extends, and the movable conductor 103 which is connected to the shaft 8 moves in a direction in which the movable-side contact 104 and the fixed-side contact 105 are separated from each other, so that the contacts are completely separated with the stored force of an opening spring 107.
- the movable core 2 returns to the initial position. Accordingly, the electromagnetic actuator 300 is brought into the demagnetized state, and the circuit breaker is brought into the opened state.
- FIG. 10 when the movable core 2 and the shaft 8 move together in the direction toward the initial position, air A between the movable core 2 and the movable-side lid plate 36 inside the yoke projection portion 7 is discharged through the air outlet 33 to the outside of the electromagnetic actuator 300.
- An arrow 33a indicates the direction in which the air A inside the electromagnetic actuator 300 is discharged through the air outlet 33 to the outside of the electromagnetic actuator 300.
- the air A discharged through the air outlet 33 during a demagnetization operation can be used for extinguishing the arc of the circuit breaker.
- the contacts of the circuit breaker are separated from each other, and arc discharge occurs.
- the arc needs to be extinguished quickly.
- the arc can be transferred to the arc extinguishing chamber side, extended, and extinguished.
- the arc extinguishing efficiency tends to increase.
- the air A which is discharged through the air outlet 33 at high speed during the demagnetization operation, for extinguishing the arc of the circuit breaker, the arc extinguishing efficiency at the time of arc generation can be improved.
- the magnetic circuit in the electromagnetic actuator 300 according to Embodiment 3 is also the same as the magnetic circuit of Embodiment 1.
- the electromagnetic actuator according to Embodiment 3 and the circuit breaker using this electromagnetic actuator have the same advantageous effects as those of the electromagnetic actuator according to Embodiment 1.
- the air inside the electromagnetic actuator can be discharged through the air discharge port and used for extinguishing the arc of the circuit breaker, so that the arc extinguishing efficiency can be improved.
- the air discharged from the electromagnetic actuator itself can be used for extinguishing the arc, the cost and the size of the circuit breaker can be reduced.
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Abstract
Description
- The present disclosure relates to an electromagnetic actuator used for a circuit breaker or the like capable of interrupting an electric path, and a circuit breaker using this electromagnetic actuator.
- Generally, in a circuit breaker, an electromagnetic actuator is used for operating a contact opening/closing operation. In the electromagnetic actuator, when a current flows through a coil, a magnetic circuit is excited, a movable core inside the electromagnetic actuator is driven in the direction toward a fixed core, and a shaft connected to the movable core moves together with the movable core, thereby operating a contact closing operation of the circuit breaker.
- As a technology related to the conventional electromagnetic actuator, for example, there is a technology described in Patent Document. In the electromagnetic actuator according to
Patent Document 1, a shaft which is an operation shaft for operating a contact closing operation of a circuit breaker is firmly fastened and fixed to a movable core by a set screw for preventing loosening. Accordingly, when a coil is energized, the shaft and the movable core move together. - In addition to such a conventional electromagnetic actuator, a circuit breaker that constantly maintains a contact closed state thereof includes a pushing mechanism in which a movable contact, which is one contact, relatively applies a contact pressure to a fixed contact, which is another contact, during closing. Accordingly, a wipe amount which is the pushing amount of the contact pressure applied to the contact is maintained, and the contacts are brought into a stable contact state during closing.
- Patent Document 1:
Japanese Laid-Open Patent Publication No. 9-199320 - However, the circuit breaker is required to be downsized, but there is a problem that the size of the circuit breaker becomes larger when the mechanism for maintaining the wipe amount between the contacts during closing is provided separately from the electromagnetic actuator.
- The present disclosure has been made to solve the above-described problem, and an object of the present disclosure is to obtain an electromagnetic actuator capable of maintaining a wipe amount during closing of a circuit breaker, and a circuit breaker that eliminates the need for providing a mechanism for maintaining a wipe amount, separately from an electromagnetic actuator and can be further downsized.
- An electromagnetic actuator according to the present disclosure includes: a tubular coil generating a magnetic flux in an axial direction thereof when a current flows therethrough; a movable core installed in a state where the movable core can reciprocate in the axial direction of the coil; a shaft surrounded by the movable core, performing an opening/closing operation between a movable-side contact and a fixed-side contact of a circuit breaker, and movable together with the movable core; a tubular yoke pipe surrounding the coil; a fixed-side lid plate disposed at one end of the yoke pipe in the axial direction of the coil; a movable-side lid plate disposed at another end of the yoke pipe in the axial direction of the coil; a fixed core disposed on an inner circumferential side of the coil from the fixed-side lid plate in a direction toward the movable-side lid plate; and a tubular yoke projection portion projecting on the inner circumferential side of the coil from the movable-side lid plate in a direction toward the fixed-side lid plate so as to face the fixed core. The movable core is disposed in a space on an inner circumferential side of the yoke projection portion, and when the movable core is excited by a current flowing through the coil, the movable core moves together with the shaft from an initial position in a direction toward the fixed core in the axial direction of the coil to bring the movable-side contact and the fixed-side contact into contact with each other to stop movement of the shaft, and then moves relative to the shaft to a position at which the movable core comes into contact with the fixed core in an excitation operation completion state.
- A circuit breaker according to the present disclosure is a circuit breaker in which the electromagnetic actuator according to the present disclosure is used for operating an opening/closing operation between the movable-side contact and the fixed-side contact.
- In the electromagnetic actuator according to present disclosure, after the movement of the shaft is stopped by bringing the movable-side contact and the fixed-side contact into contact with each other, the movable core can move relative to the shaft toward the fixed core, and a wipe amount at the time of closing of the circuit breaker can be maintained by the operation of the electromagnetic actuator itself.
- In the circuit breaker using the electromagnetic actuator according to present disclosure, it is not necessary to provide a mechanism for maintaining the wipe amount, separately from the electromagnetic actuator, so that the circuit breaker can be downsized.
-
- [
FIG. 1] FIG. 1 schematically shows a contact opened state of a circuit breaker using an electromagnetic actuator according toEmbodiment 1. - [
FIG. 2] FIG. 2 schematically shows a contact closed state of the circuit breaker using the electromagnetic actuator according toEmbodiment 1. - [
FIG. 3] FIG. 3 is a schematic cross-sectional view showing a demagnetized state of the electromagnetic actuator according toEmbodiment 1. - [
FIG. 4] FIG. 4 is a schematic cross-sectional view showing an excitation operation completion state of the electromagnetic actuator according toEmbodiment 1. - [
FIG. 5] FIG. 5 illustrates a magnetic circuit at an initial position of a movable core of the electromagnetic actuator according toEmbodiment 1. - [
FIG. 6] FIG. 6 is a schematic cross-sectional view showing a demagnetized state of an electromagnetic actuator according toEmbodiment 2. - [
FIG. 7] FIG. 7 is a schematic cross-sectional view showing an excitation operation completion state of the electromagnetic actuator according toEmbodiment 2. - [
FIG. 8] FIG. 8 illustrates a magnetic circuit at an initial position of a movable core of the electromagnetic actuator according toEmbodiment 2. - [
FIG. 9] FIG. 9 is a schematic cross-sectional view showing a demagnetized state of an electromagnetic actuator according toEmbodiment 3. - [
FIG. 10] FIG. 10 is a schematic cross-sectional view showing an excitation operation completion state of the electromagnetic actuator according toEmbodiment 3. - Hereinafter, embodiments according to the present disclosure will be described with reference to the drawings. In the following embodiments, the same components are denoted by the same reference characters.
-
FIG. 1 and FIG. 2 schematically illustrate acircuit breaker 110 using an electromagnetic actuator according toEmbodiment 1.FIG. 1 shows a contact opened state of thecircuit breaker 110, andFIG. 2 shows a contact closed state of thecircuit breaker 110. - The
circuit breaker 110 according toEmbodiment 1 is a circuit breaker that constantly maintains a contact closed state thereof by energizing a coil of an electromagnetic actuator. As shown inFIG. 1 and FIG. 2 , thecircuit breaker 110 has a movable-side contact 104 and a fixed-side contact 105 which are a pair of contacts, anelectromagnetic actuator 100 provided with ashaft 8 for operating a contact opening/closing operation, and anarc extinguishing chamber 108. - A
movable conductor 103, aflexible conductor 106, alower conductor 101, and anopening spring 107 are provided on the movable-side contact 104 side. Anupper conductor 102 is provided on the fixed-side contact 105 side. - In the
arc extinguishing chamber 108, arc discharge which occurs when the movable-side contact 104 moves away from the fixed-side contact 105 at the time of an opening operation is extinguished. - The fixed-
side contact 105, which is one of the pair of contacts, is joined to one end portion of theupper conductor 102 and electrically connected to theupper conductor 102. - The movable-
side contact 104, which is the other of the pair of contacts, is joined to one end portion of themovable conductor 103 at a position facing the fixed-side contact 105. Another end portion of themovable conductor 103 is connected to thelower conductor 101 by theflexible conductor 106. The movable-side contact 104 is electrically connected to thelower conductor 101 via themovable conductor 103 and theflexible conductor 106. - The
flexible conductor 106 is biased by theshaft 8 of theelectromagnetic actuator 100 so as to open and close the movable-side contact 104 and the fixed-side contact 105. - The
lower conductor 101, theupper conductor 102, themovable conductor 103, the movable-side contact 104, the fixed-side contact 105, and theflexible conductor 106 are composed of conductors. - The movable-
side contact 104 and the fixed-side contact 105 are energized via thelower conductor 101 and theupper conductor 102, respectively. The movable-side contact 104 becomes connected to the fixed-side contact 105 by themovable conductor 103 moving toward theupper conductor 102. In addition, the movable-side contact 104 becomes disconnected from the fixed-side contact 105 by themovable conductor 103 moving in the direction away from theupper conductor 102. - A state where the movable-
side contact 104 and the fixed-side contact 105 are connected to each other is a contact closed state, and a state where the movable-side contact 104 and the fixed-side contact 105 are separated from each other is a contact opened state. - In the
circuit breaker 110, the movable-side contact 104 and the fixed-side contact 105 are made to be connected to each other by an excitation operation of theelectromagnetic actuator 100, to bring about the contact closed state shown inFIG. 2 . In this case, thelower conductor 101 and theupper conductor 102 are energized via the movable-side contact 104 and the fixed-side contact 105. - Moreover, in the
circuit breaker 110, the movable-side contact 104 and the fixed-side contact 105 become separated from each other by a demagnetization operation of theelectromagnetic actuator 100, to bring about the contact opened state shown inFIG. 1 . In this case, the energization of thelower conductor 101 and theupper conductor 102 is stopped. - The
opening spring 107 is connected to themovable conductor 103 and is provided so as to perform contact opening on the movable-side contact 104 side of themovable conductor 103. Theopening spring 107 elastically stores a force that separates the movable-side contact 104 from the fixed-side contact 105. Contact opening and contact closing which are a contact opening operation and a contact closing operation are performed by the operation of theelectromagnetic actuator 100. When theelectromagnetic actuator 100 is driven for contact closing, contact closing is performed against the stored force of theopening spring 107. - The
shaft 8 is disposed so as to pass through the axis center of theelectromagnetic actuator 100. Themovable conductor 103 is connected to theelectromagnetic actuator 100 via theshaft 8. Theelectromagnetic actuator 100 operates the opening/closing operation between the contacts of thecircuit breaker 110. Theelectromagnetic actuator 100 moves themovable conductor 103 via theshaft 8 to control the connection between the movable-side contact 104 and the fixed-side contact 105. - Next, the configuration of the
electromagnetic actuator 100 shown inFIG. 3 andFIG. 4 will be described. -
FIG. 3 corresponds to the opened state of thecircuit breaker 110 shown inFIG. 1 , and is a cross-sectional view showing a demagnetized state of theelectromagnetic actuator 100 according toEmbodiment 1. The demagnetized state of theelectromagnetic actuator 100 shown inFIG. 3 is a state where amovable core 2 is located at an initial position. -
FIG. 4 corresponds to the closed state of thecircuit breaker 110 shown inFIG. 2 , and is a cross-sectional view showing an excitation operation completion state of theelectromagnetic actuator 100 according toEmbodiment 1. The excitation operation completion state of theelectromagnetic actuator 100 shown inFIG. 4 is a state where themovable core 2 is in contact with a fixedcore 3. - The
electromagnetic actuator 100 has atubular coil 1 which generates a magnetic flux in an axial direction thereof when a current flows therethrough, themovable core 2 which is disposed in the axial direction of thecoil 1 and is installed in a state where themovable core 2 can reciprocate in the axial direction of thecoil 1, theshaft 8 which is surrounded by themovable core 2 and is movable together with themovable core 2, atubular yoke pipe 4 which surrounds thecoil 1, a fixed-side lid plate 5 which is disposed at one end of theyoke pipe 4 in the axial direction of thecoil 1, a movable-side lid plate 6 which is disposed at the other end of theyoke pipe 4 in the axial direction of thecoil 1, the fixedcore 3 which is disposed on the inner circumferential side of thecoil 1 from the fixed-side lid plate 5 in the direction toward the movable-side lid plate 6, and a tubularyoke projection portion 7 which projects on the inner circumferential side of thecoil 1 from the movable-side lid plate 6 in the direction toward the fixed-side lid plate 5 so as to face the fixedcore 3. - In the axial direction of the
coil 1, theyoke pipe 4 is disposed between the fixed-side lid plate 5 and the movable-side lid plate 6, and the fixed-side lid plate 5 and the movable-side lid plate 6 are disposed so as to face each other. In the axial direction of thecoil 1, the fixedcore 3 faces theyoke projection portion 7 and themovable core 2 which is surrounded by theyoke projection portion 7. - Components including the
yoke pipe 4, the fixed-side lid plate 5, the movable-side lid plate 6, the fixedcore 3, and theyoke projection portion 7 are integrated with a step, and are made of a magnetic material. A typical magnetic material is, for example, iron. - Moreover, in the components including the
yoke pipe 4, the fixed-side lid plate 5, the movable-side lid plate 6, the fixedcore 3, and theyoke projection portion 7, a magnetic circuit is excited together with themovable core 2 by energizing thecoil 1. - The
coil 1 is housed in a tubular space which is formed by theyoke pipe 4, the fixed-side lid plate 5, the movable-side lid plate 6, the fixedcore 3, and theyoke projection portion 7. In addition, thecoil 1 has a tubular shape that surrounds themovable core 2, theyoke projection portion 7, and the fixedcore 3. - The
movable core 2 is disposed on the inner circumferential side of theyoke projection portion 7 so as to face the fixedcore 3, and is installed in a state where themovable core 2 can reciprocate relative to the fixedcore 3 in the axial direction of thecoil 1. Specifically, when a current flows through thecoil 1, themovable core 2 is driven so as to move toward the fixedcore 3 in the axial direction of thecoil 1. In this case, themovable core 2 moves from the initial position which is a position in the demagnetized state of theelectromagnetic actuator 100 in which the contact opened state of thecircuit breaker 110 shown inFIG. 3 is maintained, to a position at which themovable core 2 comes into contact with the fixedcore 3 and which is a position in the excitation operation completion state of theelectromagnetic actuator 100 in which the closed state of thecircuit breaker 110 shown inFIG. 4 is maintained. - Moreover, in the axial direction of the
coil 1, the length of themovable core 2 is longer than 1/2 of the length of theyoke pipe 4. At the initial position, a movablecore end surface 2a of themovable core 2 is located on the fixedcore 3 side with respect to the center position of thecoil 1 in the axial direction. As themovable core 2 becomes longer, the facing area between themovable core 2 and theyoke projection portion 7 in the axial direction becomes larger. - The magnetic resistance of the magnetic circuit is reduced by increasing the magnetic path cross-sectional area corresponding to the facing area. By increasing the facing area between the
movable core 2 and theyoke projection portion 7, the attractive force acting on themovable core 2 in an excitation maintained state can be further improved. Accordingly, the holding force between the main contacts in the closed state of thecircuit breaker 110 can be improved. - The
shaft 8 is surrounded by themovable core 2 and is disposed in the axial direction of thecoil 1. Theshaft 8 is made of a non-magnetic material. - In the axial direction of the
coil 1, theshaft 8 penetrates the fixed-side lid plate 5, the fixedcore 3, and the movable-side lid plate 6. Theshaft 8 has a firstshaft end portion 8a which is one end portion penetrating the fixed-side lid plate 5, and a secondshaft end portion 8b which is another end portion penetrating the movable-side lid plate 6. The firstshaft end portion 8a extends to themovable conductor 103 and is connected to themovable conductor 103. The secondshaft end portion 8b is formed such that the outer diameter thereof is larger than that of a portion, of theshaft 8, which is inserted into themovable core 2. - Moreover, a
shaft protrusion portion 8c and ashaft step portion 8d are formed on theshaft 8. Theshaft protrusion portion 8c faces the fixedcore 3, and theshaft step portion 8d is located at an end portion on the fixed-side lid plate 5 side of themovable core 2 so as to be adjacent to theshaft protrusion portion 8c. Theshaft protrusion portion 8c and theshaft step portion 8d are formed such that the outer diameters thereof are larger than that of the portion, of theshaft 8, which is inserted into themovable core 2. - Between the
movable core 2 and theshaft 8, a firstmovable core bearing 13 and a secondmovable core bearing 14, which are bearings for the movable core, are arranged at both ends in the axial direction of themovable core 2, respectively. - Specifically, the first movable core bearing 13 is provided on the
shaft step portion 8d of theshaft 8 at an end portion position on the fixed-side lid plate 5 side of themovable core 2. Themovable core 2 is supported by the first movable core bearing 13 so as to be movable relative to theshaft 8. By disposing the first movable core bearing 13 on theshaft 8 which is a non-magnetic component, themovable core 2 can be formed without decreasing the cross-sectional area thereof, and the attractive force can be ensured. - Moreover, the second movable core bearing 14 is provided at an end portion position on the movable-
side lid plate 6 side of themovable core 2. The second movable core bearing 14 supports themovable core 2 so as to be movable together with themovable core 2 relative to theshaft 8. - A contact-
pressure spring 9 is disposed between themovable core 2 and theshaft 8. Theshaft 8 and themovable core 2 are connected via the contact-pressure spring 9. The contact-pressure spring 9 is provided in themovable core 2, and is located between the firstmovable core bearing 13 and the second movable core bearing 14 in the axial direction. Theelectromagnetic actuator 100 is made compact. By increasing the length of themovable core 2, it is possible to increase the length of the contact-pressure spring 9. - When the
movable core 2 moves relative to theshaft 8 in the direction toward the fixedcore 3, the contact-pressure spring 9 is compressed to store a force in a direction in which themovable core 2 is separated from the fixedcore 3. - A
return spring 10 is disposed between theshaft protrusion portion 8c and the fixedcore 3. Theshaft 8 and the fixedcore 3 are connected via thereturn spring 10. Thereturn spring 10 has a tubular shape that surrounds theshaft 8 and is surrounded by the fixedcore 3. When theshaft 8 moves together with themovable core 2 in the direction toward the fixedcore 3, thereturn spring 10 is compressed to store a force in a direction in which the contacts of the circuit breaker are separated from each other. - Moreover, shaft bearings which support movement of the
shaft 8 are disposed at the fixed-side lid plate 5 and the movable-side lid plate 6, respectively, in the axial direction. Specifically, a first shaft bearing 11 is provided at a center portion of the fixed-side lid plate 5, and a second shaft bearing 12 is provided at a center portion of the movable-side lid plate 6. The first shaft bearing 11 is disposed between the fixed-side lid plate 5 and the firstshaft end portion 8a of theshaft 8 which penetrates the fixed-side lid plate 5. The second shaft bearing 12 is disposed between the movable-side lid plate 6 and the secondshaft end portion 8b of theshaft 8 which penetrates the movable-side lid plate 6. Theshaft 8 can move in the axial direction of thecoil 1 while being supported by the first shaft bearing 11 and the second shaft bearing 12. - Next, the structure of the fixed
core 3 and the positional relationship of the fixedcore 3 with themovable core 2 in theelectromagnetic actuator 100 according toEmbodiment 1 will be described. - The
movable core 2 and the fixedcore 3 each have a tubular shape that surrounds theshaft 8. In a direction perpendicular to the axial direction of thecoil 1, themovable core 2 and the fixedcore 3 have the movablecore end surface 2a and a fixedcore end surface 3a which face each other. The movablecore end surface 2a is an annular surface facing the fixedcore end surface 3a, and the fixedcore end surface 3a is an annular surface facing the movablecore end surface 2a. - At the initial position, a gap s1 having a predetermined distance is provided at the facing position between the movable
core end surface 2a and the fixedcore end surface 3a. Themovable core 2 is excited and driven in the axial direction toward the fixedcore 3, the gap s1 becomes smaller as themovable core 2 moves, and in the excitation operation completion state, the movablecore end surface 2a comes into contact with the fixedcore end surface 3a, so that the gap s1 becomes zero. - The fixed
core end surface 3a is located on the fixed-side lid plate 5 side with respect to the center in the axial direction of thecoil 1. A surface at which the movablecore end surface 2a of themovable core 2 comes into contact with the fixedcore end surface 3a of the fixedcore 3 in the excitation operation completion state in which themovable core 2 has been excited and driven in the axial direction toward the fixedcore 3, as shown inFIG. 4 , is referred to as acontact surface 16. - The position of the
contact surface 16 is the same as the position of the fixedcore end surface 3a, and thecontact surface 16 between themovable core 2 and the fixedcore 3 in the excitation operation completion state is located on themovable core 2 moving direction side with respect to the center in the axial direction of thecoil 1. That is, thecontact surface 16 is located on the fixed-side lid plate 5 side with respect to the center in the axial direction of thecoil 1. - Accordingly, a sufficient distance can be obtained between the
contact surface 16 and the movablecore end surface 2a at the initial position. In addition, it is possible to increase the length in the axial direction of themovable core 2, so that the facing area with theyoke projection portion 7 can be increased and the attractive force can be increased. - Moreover, as shown in
FIG. 3 , in the fixedcore 3, a fixedcore recess 3b which faces theshaft protrusion portion 8c of theshaft 8 and is recessed so as to house theshaft protrusion portion 8c and thereturn spring 10 is formed at a center portion in the axial direction of the fixedcore end surface 3a. A fixedcore step portion 3c is provided so as to be stepped on an inner wall surface of the fixedcore recess 3b and face the shaft protrusion portion. In the excitation operation completion state shown inFIG. 4 , theshaft protrusion portion 8c is surrounded by the fixedcore recess 3b so as to be housed in the fixedcore recess 3b, and contacts the fixedcore 3 via thereturn spring 10. - Next, the structure of the
yoke projection portion 7 and the position relationship of theyoke projection portion 7 with themovable core 2 and the fixedcore 3 in theelectromagnetic actuator 100 according toEmbodiment 1 will be described. - In the
electromagnetic actuator 100 according toEmbodiment 1, theyoke projection portion 7 has a yokemain projection portion 7a which is disposed on the movable-side lid plate 6 side, and a yokenarrow projection portion 7b which extends from the yokemain projection portion 7a toward the fixed-side lid plate 5 side. Theyoke projection portion 7 faces the fixedcore 3, and is disposed such that the yokenarrow projection portion 7b extends in the direction toward the fixedcore 3. A yoke projection portiondistal end surface 7c which is an end surface, of theyoke projection portion 7, facing the fixedcore 3 projects so as to be closer to the fixedcore 3 than the movablecore end surface 2a is at the initial position. A gap g1 having a predetermined distance is provided at the facing position between the yoke projection portiondistal end surface 7c and the fixedcore end surface 3a. The gap g1 is smaller than the gap s1 between the fixedcore end surface 3a and the movablecore end surface 2a at the initial position. - The inner diameter of the yoke
main projection portion 7a and the inner diameter of the yokenarrow projection portion 7b are equal to each other, and the outer diameter of the yokemain projection portion 7a is larger than the outer diameter of the yokenarrow projection portion 7b. The yokemain projection portion 7a and the yokenarrow projection portion 7b may be integrally formed or may be formed as separate components. Both the yokemain projection portion 7a and the yokenarrow projection portion 7b have a yoke projection portioninner wall surface 7d which is an inner wall surface of theyoke projection portion 7. The characteristics of the attractive force applied to themovable core 2 can be adjusted by adjusting the configuration of theyoke projection portion 7 such as the outer diameter difference between the yokemain projection portion 7a and the yokenarrow projection portion 7b and the width of the yokenarrow projection portion 7b. - In the
yoke projection portion 7, the yoke projection portioninner wall surface 7d faces a movable coreouter wall surface 2b, which is an outer wall surface of themovable core 2, so as to surround themovable core 2. Theyoke projection portion 7 has the yokenarrow projection portion 7b which extends from the yokemain projection portion 7a, and by increasing the length of themovable core 2, the facing area between themovable core 2 and theyoke projection portion 7 becomes larger, that is, the facing area between the movable coreouter wall surface 2b and the yoke projection portioninner wall surface 7d becomes larger. - Next, the operation of the
electromagnetic actuator 100 will be described. - By energizing the
coil 1, the magnetic circuit composed of themovable core 2, the fixedcore 3, the fixed-side lid plate 5, theyoke pipe 4, the movable-side lid plate 6, and theyoke projection portion 7 is excited, a magnetic attractive force acts on themovable core 2, and themovable core 2 is driven in the direction toward the fixedcore 3. Themovable core 2 shown inFIG. 3 is driven from the initial position to the position at which themovable core 2 comes into contact with the fixedcore 3 and which is a position in the excitation operation completion state shown inFIG. 4 . Thecircuit breaker 110 is brought into the closed state shown inFIG. 2 from the opened state shown inFIG. 1 . - As the
movable core 2 moves in the direction toward the fixedcore 3 side, the contact-pressure spring 9 which connects themovable core 2 and theshaft 8 is pressed by the movingmovable core 2, so that theshaft 8 moves together with themovable core 2 from the movable-side lid plate 6 side toward the fixed-side lid plate 5 side. Themovable conductor 103 which is connected to theshaft 8 moves in the left direction on the drawing sheet inFIG. 1 so as to bring the movable-side contact 104 and the fixed-side contact 105 into contact with each other. Thereturn spring 10 between theshaft protrusion portion 8c and the fixedcore 3 is compressed to store a force. When the movable-side contact 104 and the fixed-side contact 105 come into contact with each other, theshaft 8 stops. After the movement of theshaft 8 is stopped, themovable core 2 is further driven in the direction toward the fixedcore 3 relative to theshaft 8 by the magnetic attractive force. Then, the movablecore end surface 2a of themovable core 2 and the fixedcore end surface 3a of the fixedcore 3 come into contact with each other to complete the excitation operation, and the circuit breaker is brought into the closed state. - After the movement of the
shaft 8 is stopped by bringing the movable-side contact 104 and the fixed-side contact 105 into contact with each other, themovable core 2 moves relative to theshaft 8, thereby further applying a contact pressure to the movable-side contact 104 and the fixed-side contact 105 via theshaft 8. Accordingly, a wipe amount at the time of closing can be maintained by the operation of the electromagnetic actuator itself. - As shown in
FIG. 4 , in the excitation operation completion state in which themovable core 2 is in contact with the fixedcore 3, thereturn spring 10 is compressed and theshaft 8 contacts the fixedcore 3 via thereturn spring 10. At this time, theshaft protrusion portion 8c is surrounded by the fixedcore recess 3b so as to be housed in the fixedcore recess 3b, and does not completely contact the fixedcore step portion 3c in the fixedcore recess 3b, so that there is agap 16a therebetween. - Since the
gap 16a exists between theshaft protrusion portion 8c and the fixedcore step portion 3c, themovable core 2 can apply a contact pressure between the contacts via theshaft 8. - Also in the excitation operation completion state, the
shaft protrusion portion 8c contacts the fixedcore step portion 3c via thereturn spring 10 such that the stored force of the contact-pressure spring 9 remains. Since thegap 16a exists, the stored force of the contact-pressure spring 9 can be released when the magnetic circuit is demagnetized. In the electromagnetic actuator, an attractive force may act between the movable core and the fixed core due to the influence of the residual magnetic field, and themovable core 2 can be separated from the fixedcore 3 by using the stored force of the contact-pressure spring 9. Since the stored force of the contact-pressure spring 9 can be used, the size of thereturn spring 10 which is provided on the fixedcore 3 side can be reduced, so that thereturn spring 10 can be downsized. - When the magnetic circuit is demagnetized by stopping the energization of the
coil 1, the magnetic attractive force disappears, the contact-pressure spring 9 extends, and themovable core 2 moves in a direction opposite to a direction in which the fixedcore 3 is disposed. The secondshaft end portion 8b is brought into contact with themovable core 2, and theshaft 8 moves together with the movable core. Thereturn spring 10 extends, and themovable conductor 103 which is connected to theshaft 8 moves in the right direction on the drawing sheet inFIG. 1 so as to separate the movable-side contact 104 and the fixed-side contact 105 from each other, so that the contacts are completely separated with the stored force of theopening spring 107. Themovable core 2 returns to the initial position. Accordingly, theelectromagnetic actuator 100 is brought into the demagnetized state, and thecircuit breaker 110 is brought into the opened state shown inFIG. 1 . -
FIG. 5 illustrates the magnetic circuit at the initial position of themovable core 2 of theelectromagnetic actuator 100 according toEmbodiment 1. - As shown in
FIG. 5 , at the initial position, the gap g1 between the yoke projection portiondistal end surface 7c and the fixedcore end surface 3a is smaller than the gap s1 between the movablecore end surface 2a and the fixedcore end surface 3a. Therefore, amagnetic flux 24 in the axial direction which is generated in the magnetic circuit by energizing thecoil 1 has amagnetic flux 24a which passes through themovable core 2, and amagnetic flux 24b which passes through theyoke projection portion 7. A part of themagnetic flux 24 in the axial direction flows from the yokemain projection portion 7a of theyoke projection portion 7 through the yokenarrow projection portion 7b to the fixedcore 3, and the magnetic flux flowing through themovable core 2 becomes smaller. Until the position of the movablecore end surface 2a of themovable core 2 moves past the yoke projection portiondistal end surface 7c, the driving force applied to themovable core 2 is reduced, so that it is possible to slow down the excitation operation of theelectromagnetic actuator 100. Accordingly, it is possible to close the contacts of thecircuit breaker 110 at low speed. - Moreover, when the
movable core 2 moves toward the fixedcore 3 away from the movable-side lid plate 6, the magnetic flux passes through themovable core 2 and the fixedcore 3 from theyoke projection portion 7. As themovable core 2 moves, the gap s1 between the movablecore end surface 2a and the fixedcore end surface 3a becomes smaller. When the position of the movablecore end surface 2a of themovable core 2 moves past the yoke projection portiondistal end surface 7c, the gap g1 between the yoke projection portiondistal end surface 7c and the fixedcore end surface 3a becomes larger than the gap s1 between the movablecore end surface 2a and the fixedcore end surface 3a, so that almost all of the magnetic flux in the axial direction passes through themovable core 2 from theyoke projection portion 7. In the maintained state where the excitation operation is completed, almost all of the magnetic flux in the axial direction passes through themovable core 2. Therefore, after the movablecore end surface 2a of themovable core 2 moves past the yoke projection portiondistal end surface 7c of theyoke projection portion 7, the driving force applied to themovable core 2 becomes larger, so that the attractive force in the excitation maintained state can be improved. - Also, as described above, the
contact surface 16 between themovable core 2 and the fixedcore 3 is located on themovable core 2 moving direction side with respect to the center in the axial direction of thecoil 1, and by increasing the length of themovable core 2 and extending the yokenarrow projection portion 7b of theyoke projection portion 7 in the direction toward the fixedcore 3, the facing area between theyoke projection portion 7 and themovable core 2 in the direction perpendicular to the axial direction becomes larger, so that the attractive force in the excitation maintained state can be further improved. - In the electromagnetic actuator according to
Embodiment 1, after the movement of the shaft is stopped by bringing the movable-side contact and the fixed-side contact into contact with each other, the movable core can move relative to the shaft toward the fixed core, and a wipe amount at the time of closing of the circuit breaker can be maintained by the operation of the electromagnetic actuator itself. - In the circuit breaker using the electromagnetic actuator according to
Embodiment 1, it is not necessary to provide a mechanism for maintaining the wipe amount, separately from the electromagnetic actuator, so that the circuit breaker can be downsized. - Moreover, in the electromagnetic actuator according to
Embodiment 1, since the contact surface between the movable core and the fixed core is located on the movable core moving direction side with respect to the center position of the coil in the axial direction of the coil, the distance between the contact surface and the initial position can be ensured. Even when the length in the axial direction of the movable core is increased, the movable core can be formed without projecting outward from the movable-side lid plate at the initial position, so that it is possible to reduce the external dimensions of the electromagnetic actuator. Accordingly, the circuit breaker using the electromagnetic actuator can be downsized. - Furthermore, in the electromagnetic actuator according to
Embodiment 1, owing to the configuration in which the yoke narrow projection portion is provided in the yoke projection portion, the effects of slowing down the excitation operation and improving the attractive force in the excitation maintained state are achieved. Accordingly, the contacts of the circuit breaker using the electromagnetic actuator can be closed at low speed, and the holding force between the contacts in the closed state can be improved. -
FIGS. 6 and7 are cross-sectional views of anelectromagnetic actuator 200 according toEmbodiment 2 of the present disclosure. -
FIG. 6 is a cross-sectional view showing a demagnetized state of theelectromagnetic actuator 200 according toEmbodiment 2, corresponding to the opened state of the circuit breaker shown inFIG. 1 .FIG. 6 is a cross-sectional view showing a state where amovable core 2 is at an initial position in the demagnetized state of theelectromagnetic actuator 200. -
FIG. 7 is a cross-sectional view showing an excitation operation completion state of theelectromagnetic actuator 200 according toEmbodiment 2, corresponding to the closed state of the circuit breaker shown inFIG. 2 . The excitation operation completion state of theelectromagnetic actuator 200 shown inFIG. 7 is a state where themovable core 2 is in contact with a fixedcore 3. - Similar to the
electromagnetic actuator 100 shown inFIG. 1 and FIG. 2 , theelectromagnetic actuator 200 serves to bias the movable contact of the circuit breaker in the closing direction and is used for operating an opening/closing operation between the contacts. - In
Embodiment 2, the same components as those inEmbodiment 1 of the present disclosure are denoted by the same reference characters, and the description of the same or corresponding parts is omitted. Hereinafter, the differences of theelectromagnetic actuator 200 according toEmbodiment 2 fromEmbodiment 1 will be described with reference to the drawings. - As shown in
FIGS. 6 and7 , theelectromagnetic actuator 200 has atubular coil 1 which generates a magnetic flux in an axial direction thereof when a current flows therethrough, themovable core 2 which is disposed in the axial direction of thecoil 1 and is installed in a state where themovable core 2 can reciprocate in the axial direction of thecoil 1, ashaft 8 which is surrounded by themovable core 2 and is movable together with themovable core 2, atubular yoke pipe 4 which surrounds thecoil 1, a fixed-side lid plate 5 which is disposed at one end of theyoke pipe 4 in the axial direction of thecoil 1, a movable-side lid plate 6 which is disposed at the other end of theyoke pipe 4 in the axial direction of thecoil 1, the fixedcore 23 which is disposed on the inner circumferential side of thecoil 1 from the fixed-side lid plate 5 in the direction toward the movable-side lid plate 6, and a tubularyoke projection portion 27 which projects on the inner circumferential side of thecoil 1 from the movable-side lid plate 6 in the direction toward the fixed-side lid plate 5 so as to face the fixedcore 23. - Components including the
yoke pipe 4, the fixed-side lid plate 5, the movable-side lid plate 6, the fixedcore 23, and theyoke projection portion 27 are integrated with a step, and are made of a magnetic material. A typical magnetic material is, for example, iron. - Moreover, in the components including the
yoke pipe 4, the fixed-side lid plate 5, the movable-side lid plate 6, the fixedcore 23, and theyoke projection portion 27, a magnetic circuit is excited together with themovable core 2 by energizing thecoil 1. - In
Embodiment 2, the configurations of the fixedcore 23 and theyoke projection portion 27 are different from the configurations of the fixedcore 3 and theyoke projection portion 7 ofEmbodiment 1. In theelectromagnetic actuator 200 according toEmbodiment 2, the configuration other than the fixedcore 23 and the tubularyoke projection portion 27 is the same as inEmbodiment 1. The same advantageous effects are achieved. - Next, the structure of the tubular
yoke projection portion 27 and the positional relationship of the tubularyoke projection portion 27 with themovable core 2 in theelectromagnetic actuator 200 according toEmbodiment 1 will be described. - The tubular
yoke projection portion 27 projects from the movable-side lid plate 6 in the direction toward the fixed-side lid plate 5 so as to surround a part of themovable core 2 at the initial position, and both the outer diameter and the inner diameter of the tubularyoke projection portion 27 are uniform. The tubularyoke projection portion 27 has a yoke projection portiondistal end surface 27a which is an annular end surface facing the fixedcore 23, and a yoke projection portioninner wall surface 27b which faces a movable coreouter wall surface 2b which is an outer wall surface of themovable core 2. - Next, the structure of the fixed
core 23 and the positional relationship of the fixedcore 23 with themovable core 2 and the tubularyoke projection portion 27 in theelectromagnetic actuator 200 according toEmbodiment 1 will be described. - The fixed
core 23 has a fixedcore base portion 23a which is disposed on the fixed-side lid plate 5 side, and a fixed corenarrow projection portion 23b which extends from the fixedcore base portion 23a in the direction toward the movable-side lid plate 6. The fixedcore base portion 23a and the fixed corenarrow projection portion 23b may be integrally formed or may be formed as separate components. - The fixed
core base portion 23a is disposed so as to face themovable core 2 and the tubularyoke projection portion 27 which surrounds themovable core 2. The fixedcore base portion 23a has a fixedcore end surface 23c which is an end surface facing themovable core 2. The fixedcore end surface 23c is an annular surface facing a movablecore end surface 2a, and is located on the fixed-side lid plate 5 side with respect to the center in the axial direction of thecoil 1. - At the initial position, a gap s2 having a predetermined distance is provided at the facing position between the movable
core end surface 2a and the fixedcore end surface 23c. Themovable core 2 is excited and driven in the axial direction toward the fixedcore 23, the gap s2 becomes smaller as themovable core 2 moves, and in the excitation operation completion state, the movablecore end surface 2a comes into contact with the fixedcore end surface 23c, so that the gap s2 becomes zero. - A surface at which the movable
core end surface 2a of themovable core 2 comes into contact with the fixedcore end surface 23c of the fixedcore 23 in the excitation operation completion state as shown inFIG. 7 , is referred to as acontact surface 26. The position of thecontact surface 26 is the same as the position of the fixedcore end surface 23c, and is located on themovable core 2 moving direction side with respect to the center position in the axial direction of thecoil 1. That is, thecontact surface 26 is located on the fixed-side lid plate 5 side with respect to the center in the axial direction of thecoil 1. - Accordingly, a sufficient distance can be obtained between the
contact surface 26 and the movablecore end surface 2a at the initial position. - Moreover, as shown in
FIG. 6 , in the fixedcore base portion 23a, a fixed core recess 23f which faces ashaft protrusion portion 8c of theshaft 8 and is recessed so as to house theshaft protrusion portion 8c and areturn spring 10 is formed at a center portion in the axial direction of the fixedcore end surface 23c. A fixedcore step portion 23g is provided so as to be stepped on an inner wall surface of the fixed core recess 23f and face the shaft protrusion portion. In the excitation operation completion state shown inFIG. 7 , theshaft protrusion portion 8c is surrounded by the fixedcore step portion 23g so as to be housed in the fixedcore step portion 23g. - The fixed core
narrow projection portion 23b extends in the direction toward themovable core 2, and has a tubular shape that surrounds a movable coredistal end portion 2c which is a distal end portion of themovable core 2 in a direction in which themovable core 2 moves toward the fixedcore base portion 23a. The fixed corenarrow projection portion 23b has a fixed coredistal end surface 23d which is an annular end surface facing the tubularyoke projection portion 27, and a fixed coreinner wall surface 23e which is an inner wall surface facing the movable coreouter wall surface 2b. At the initial position, in themovable core 2, in the axial direction, the movable coredistal end portion 2c is surrounded by the fixed corenarrow projection portion 23b, and a portion on the movable-side lid plate 6 side other than the movable coredistal end portion 2c is surrounded by the tubularyoke projection portion 27. - The fixed core
distal end surface 23d projects so as to be closer to the tubularyoke projection portion 27 than the position of the movablecore end surface 2a is at the initial position. A gap g2 having a predetermined distance is provided at the facing position between the yoke projection portiondistal end surface 27a and the fixed coredistal end surface 23d. The gap g2 is smaller than the gap s2 at the initial position. - Next, the operation of the
electromagnetic actuator 200 will be described. - By energizing the
coil 1, the magnetic circuit composed of themovable core 2, the fixedcore 23, the fixed-side lid plate 5, theyoke pipe 4, the movable-side lid plate 6, and theyoke projection portion 27 is excited, a magnetic attractive force acts on themovable core 2, and themovable core 2 is driven in the direction toward the fixedcore 23. Themovable core 2 shown inFIG. 6 is driven from the initial position to the position at which themovable core 2 comes into contact with the fixedcore 23 and which is a position in the excitation operation completion state shown inFIG. 7 . Thecircuit breaker 110 is brought into the closed state shown inFIG. 2 from the opened state shown inFIG. 1 . - As the
movable core 2 moves in the direction toward the fixedcore 23 side, the contact-pressure spring 9 which connects themovable core 2 and theshaft 8 is pressed by the movingmovable core 2, so that theshaft 8 moves together with themovable core 2 in the axial direction from the movable-side lid plate 6 side toward the fixed-side lid plate 5 side. The contacts of the circuit breaker come into contact with each other via a movable conductor connected to theshaft 8. When the contacts come into contact with each other, theshaft 8 stops. After the movement of theshaft 8 is stopped, themovable core 2 is driven by the magnetic attractive force so as to further move relative to theshaft 8 to the position at which themovable core 2 comes into contact with the fixedcore 23. Then, the movablecore end surface 2a of themovable core 2 and the fixedcore end surface 23c of the fixedcore 23 come into contact with each other to complete the excitation operation, and the circuit breaker is brought into the closed state. - After the movement of the
shaft 8 is stopped by bringing the contacts of the circuit breaker into contact with each other, themovable core 2 moves relative to theshaft 8, thereby further applying a contact pressure to the contacts of the circuit breaker via theshaft 8. Accordingly, a wipe amount at the time of closing can be maintained by the operation of the electromagnetic actuator itself. - As shown in
FIG. 7 , in the excitation operation completion state in which themovable core 2 is in contact with the fixedcore 23, thereturn spring 10 is compressed and theshaft 8 contacts the fixedcore 23 via thereturn spring 10. At this time, theshaft protrusion portion 8c is surrounded by the fixed core recess 23f so as to be housed in the fixed core recess 23f, and does not completely contact the fixedcore step portion 23g in the fixed core recess 23f, so that there is agap 26a therebetween. - Since the
gap 26a exists between theshaft protrusion portion 8c and the fixedcore step portion 23g, themovable core 2 can apply a contact pressure between the contacts via theshaft 8. - Also in the excitation operation completion state, the
shaft protrusion portion 8c contacts the fixedcore step portion 23g via thereturn spring 10 such that the stored force of the contact-pressure spring 9 remains. Since thegap 26a exists, the stored force of the contact-pressure spring 9 can be released when the magnetic circuit is demagnetized. In the electromagnetic actuator, an attractive force may act between the movable core and the fixed core due to the influence of the residual magnetic field, and themovable core 2 can be separated from the fixedcore 23 by using the stored force of the contact-pressure spring 9. Since the stored force of the contact-pressure spring 9 can be used, the size of thereturn spring 10 which is provided on the fixedcore 23 side can be reduced, so that thereturn spring 10 can be downsized. - When the magnetic circuit is demagnetized by stopping the energization of the
coil 1, the magnetic attractive force disappears, the contact-pressure spring 9 extends, and themovable core 2 moves in a direction opposite to a direction in which the fixedcore 23 is disposed. Themovable core 2 is brought into contact with the secondshaft end portion 8b, and theshaft 8 moves together with the movable core. Thereturn spring 10 extends, and themovable conductor 103 which is connected to theshaft 8 moves in a direction in which the movable-side contact 104 and the fixed-side contact 105 are separated from each other, so that the contacts are completely separated with the stored force of anopening spring 107. Themovable core 2 returns to the initial position. Accordingly, theelectromagnetic actuator 200 is brought into the demagnetized state, and the circuit breaker is brought into the opened state. -
FIG. 8 illustrates the magnetic circuit at the initial position of themovable core 2 of theelectromagnetic actuator 200 according toEmbodiment 2. - As shown in
FIG. 8 , at the initial position, the gap g2 between the yoke projection portiondistal end surface 27a and the fixed coredistal end surface 23d is smaller than the gap s2 between the movablecore end surface 2a and the fixedcore end surface 23c. Therefore, amagnetic flux 28 in the axial direction which is generated in the magnetic circuit by energizing thecoil 1 has amagnetic flux 28a which passes through themovable core 2, and amagnetic flux 28b which passes through the fixed corenarrow projection portion 23b from the tubularyoke projection portion 27. A part of themagnetic flux 28 in the axial direction flows from the tubularyoke projection portion 27 through the fixed corenarrow projection portion 23b to the fixedcore 23, and the magnetic flux flowing through themovable core 2 becomes smaller. The driving force applied to themovable core 2 is reduced, so that it is possible to slow down the excitation operation of theelectromagnetic actuator 200. Accordingly, it is possible to close the contacts of the circuit breaker at low speed. - In the electromagnetic actuator according to
Embodiment 2, after the movement of the shaft is stopped by bringing the movable-side contact and the fixed-side contact into contact with each other, the movable core can move relative to the shaft toward the fixed core, and a wipe amount at the time of closing of the circuit breaker can be maintained by the operation of the electromagnetic actuator itself. - In the circuit breaker using the electromagnetic actuator according to
Embodiment 2, it is not necessary to provide a mechanism for maintaining the wipe amount, separately from the electromagnetic actuator, so that the circuit breaker can be downsized. - Moreover, in the electromagnetic actuator according to
Embodiment 2, since the contact surface between the movable core and the fixed core is located on the movable core moving direction side with respect to the center position of the coil in the axial direction of the coil, the distance between the contact surface and the initial position can be ensured. Even when the length in the axial direction of the movable core is increased, the movable core can be formed without projecting outward from the movable-side lid plate at the initial position, so that it is possible to reduce the external dimensions of the electromagnetic actuator. Accordingly, the circuit breaker using the electromagnetic actuator can be downsized. - Furthermore, in the electromagnetic actuator according to
Embodiment 2, owing to the configuration of the fixed core provided with the fixed core narrow projection portion, the slowdown of the excitation operation can be improved. Accordingly, it is possible to close the contacts of the circuit breaker, which uses this electromagnetic actuator, at low speed. -
FIGS. 9 and10 are cross-sectional views of anelectromagnetic actuator 300 according toEmbodiment 3 of the present disclosure. -
FIG. 9 corresponds to the opened state of thecircuit breaker 110 shown inFIG. 1 , and is a cross-sectional view showing a demagnetized state of theelectromagnetic actuator 300 according toEmbodiment 3. The demagnetized state of theelectromagnetic actuator 300 shown inFIG. 9 is a state where amovable core 2 of theelectromagnetic actuator 300 is located at an initial position. -
FIG. 10 corresponds to the closed state of thecircuit breaker 110 shown inFIG. 2 , and is a cross-sectional view showing an excitation operation completion state of theelectromagnetic actuator 300 according toEmbodiment 3. The excitation operation completion state of theelectromagnetic actuator 300 shown inFIG. 10 is a state where themovable core 2 is in contact with a fixedcore 3. - Similar to the
electromagnetic actuator 100 shown inFIG. 1 and FIG. 2 , theelectromagnetic actuator 300 serves to bias the movable contact of the circuit breaker in the closing direction and is used for operating an opening/closing operation between the contacts. - In
Embodiment 3, the same components as those inEmbodiment 1 of the present disclosure are denoted by the same reference characters, and the description of the same or corresponding parts is omitted. Hereinafter, the differences of theelectromagnetic actuator 300 according toEmbodiment 3 fromEmbodiment 1 will be described with reference to the drawings. - As shown in
FIGS. 9 and10 , the electromagnetic actuator 300 has a tubular coil 1 which generates a magnetic flux in an axial direction thereof when a current flows therethrough, the movable core 2 in which a tubular space for housing the coil is formed and which is disposed in the axial direction of the coil 1 and is installed in a state where the movable core 2 can reciprocate in the axial direction of the coil 1, a shaft 8 which is surrounded by the movable core 2 and is movable together with the movable core 2, a tubular yoke pipe 4 which surrounds the coil 1, a fixed-side lid plate 5 which is disposed at one end of the yoke pipe 4 in the axial direction of the coil 1, a movable-side lid plate 36 which is disposed at the other end of the yoke pipe 4 in the axial direction of the coil 1, the fixed core 3 which is disposed on the inner circumferential side of the coil 1 from the fixed-side lid plate 5 in the direction toward the movable-side lid plate 36, and a tubular yoke projection portion 7 which projects on the inner circumferential side of the coil 1 from the movable-side lid plate 36 in the direction toward the fixed-side lid plate 5 so as to face the fixed core 3. - Components including the
yoke pipe 4, the fixed-side lid plate 5, the movable-side lid plate 36, the fixedcore 3, and theyoke projection portion 7 are integrated with a step, and are made of a magnetic material. A typical magnetic material is, for example, iron. - Moreover, in the components including the
yoke pipe 4, the fixed-side lid plate 5, the movable-side lid plate 36, the fixedcore 3, and theyoke projection portion 7, a magnetic circuit is excited together with themovable core 2 by energizing thecoil 1. - In
Embodiment 3, the configuration of the movable-side lid plate 36 is different from the configuration of the movable-side lid plate 6 ofEmbodiment 1. - As shown in
FIG. 9 , in the movable-side lid plate 36, anair outlet 33 is provided at a portion surrounded by theyoke projection portion 7, so as to penetrate the movable-side lid plate 36. - Moreover, an airtight bearing which supports movement of the
movable core 2 relative to theyoke projection portion 7 and blocks outflow of air is provided between themovable core 2 and theyoke projection portion 7. The airtight bearing is movable together with themovable core 2 and is disposed such that the air inside the electromagnetic actuator does not leak from between themovable core 2 and theyoke projection portion 7. - A plurality of airtight bearings can be provided between the
movable core 2 and theyoke projection portion 7, and the airtightness and the holding stability of themovable core 2 can be improved. - As shown in
FIG. 9 andFIG. 10 , a thirdmovable core bearing 31 and a fourthmovable core bearing 32, which are airtight bearings, are provided at both end portions of themovable core 2, respectively. The thirdmovable core bearing 31 and the fourth movable core bearing 32 have a hermetically sealed configuration such that the air inside the electromagnetic actuator does not leak from between themovable core 2 and theyoke projection portion 7, and support themovable core 2 so as to be movable together with themovable core 2 relative to theyoke projection portion 7. - Moreover, a
spring pressing plate 34 is provided between themovable core 2 and a contact-pressure spring 9. When themovable core 2 moves in the direction toward the fixedcore 3 side, the contact-pressure spring 9 is pressed by the movingmovable core 2 via thespring pressing plate 34, and theshaft 8 moves together with themovable core 2 in the axial direction from the movable-side lid plate 6 side toward the fixed-side lid plate 5 side. - The
spring pressing plate 34 is also in contact with themovable core 2 and theshaft 8, and also has a function of closing the gap between themovable core 2 and theshaft 8 such that the air inside themovable core 2 does not leak. - In the
electromagnetic actuator 300 according toEmbodiment 3, the configuration other than the configuration of the movable-side lid plate 36 and the airtight bearings between themovable core 2 and theyoke projection portion 7 is the same as inEmbodiment 1. The same advantageous effects are achieved. - As for the operation of the
electromagnetic actuator 300 according toEmbodiment 3, the difference fromEmbodiment 1 will be described. - The
electromagnetic actuator 300 is the same as inEmbodiment 1, except that in theelectromagnetic actuator 300, by stopping the energization of thecoil 1, the magnetic circuit is demagnetized, and when themovable core 2 moves from the position at which themovable core 2 comes into contact with the fixedcore 3, to the initial position, themovable core 2 discharges air through theair outlet 33. - When the magnetic circuit is demagnetized by stopping the energization of the
coil 1, the magnetic attractive force disappears, the contact-pressure spring 9 extends, and themovable core 2 moves in a direction opposite to a direction in which the fixedcore 3 is disposed. Themovable core 2 is brought into contact with the secondshaft end portion 8b, and theshaft 8 moves together with themovable core 2. Thereturn spring 10 extends, and themovable conductor 103 which is connected to theshaft 8 moves in a direction in which the movable-side contact 104 and the fixed-side contact 105 are separated from each other, so that the contacts are completely separated with the stored force of anopening spring 107. Themovable core 2 returns to the initial position. Accordingly, theelectromagnetic actuator 300 is brought into the demagnetized state, and the circuit breaker is brought into the opened state. - In
FIG. 10 , when themovable core 2 and theshaft 8 move together in the direction toward the initial position, air A between themovable core 2 and the movable-side lid plate 36 inside theyoke projection portion 7 is discharged through theair outlet 33 to the outside of theelectromagnetic actuator 300. Anarrow 33a indicates the direction in which the air A inside theelectromagnetic actuator 300 is discharged through theair outlet 33 to the outside of theelectromagnetic actuator 300. The air A discharged through theair outlet 33 during a demagnetization operation can be used for extinguishing the arc of the circuit breaker. - With the demagnetization operation of the electromagnetic actuator, the contacts of the circuit breaker are separated from each other, and arc discharge occurs. The arc needs to be extinguished quickly. By blowing air to the arc generated between the contacts, the arc can be transferred to the arc extinguishing chamber side, extended, and extinguished. As the amount of air blown to the arc increases, the arc extinguishing efficiency tends to increase. By using the air A, which is discharged through the
air outlet 33 at high speed during the demagnetization operation, for extinguishing the arc of the circuit breaker, the arc extinguishing efficiency at the time of arc generation can be improved. - The magnetic circuit in the
electromagnetic actuator 300 according toEmbodiment 3 is also the same as the magnetic circuit ofEmbodiment 1. - The electromagnetic actuator according to
Embodiment 3 and the circuit breaker using this electromagnetic actuator have the same advantageous effects as those of the electromagnetic actuator according toEmbodiment 1. - Furthermore, when the electromagnetic actuator is demagnetized, the air inside the electromagnetic actuator can be discharged through the air discharge port and used for extinguishing the arc of the circuit breaker, so that the arc extinguishing efficiency can be improved. In addition, since the air discharged from the electromagnetic actuator itself can be used for extinguishing the arc, the cost and the size of the circuit breaker can be reduced.
- It is noted that, within the scope of the present disclosure, the embodiments described in the present disclosure may be combined with each other, or each of the embodiments may be modified or simplified as appropriate.
-
- 1
- coil
- 2
- movable core
- 2a
- movable core end surface
- 2b
- movable core outer wall surface
- 2c
- movable core distal end portion
- 3
- fixed core
- 3a
- fixed core end surface
- 3b
- fixed core recess
- 3c
- fixed core step portion
- 4
- yoke pipe
- 5
- fixed-side lid plate
- 6
- movable-side lid plate
- 7
- yoke projection portion
- 7a
- yoke main projection portion
- 7b
- yoke narrow projection portion
- 7c
- yoke projection portion distal end surface
- 7d
- yoke projection portion inner wall surface
- 8
- shaft
- 8a
- first shaft end portion
- 8b
- second shaft end portion
- 9
- contact-pressure spring
- 10
- return spring
- 11
- first shaft bearing
- 12
- second shaft bearing
- 13
- first movable core bearing
- 14
- second movable core bearing
- 23
- fixed core
- 23a
- fixed core base portion
- 23b
- fixed core narrow projection portion
- 23c
- fixed core end surface
- 23d
- fixed core distal end surface
- 23e
- fixed core inner wall surface
- 23f
- fixed core recess
- 23g
- fixed core step portion
- 24
- magnetic flux
- 27
- yoke projection portion
- 27a
- yoke projection portion distal end surface
- 27b
- yoke projection portion inner wall surface
- 28
- magnetic flux
- 31
- third movable core bearing
- 32
- fourth movable core bearing
- 33
- air outlet
- 36
- movable-side lid plate
- 100
- electromagnetic actuator
- 110
- circuit breaker
- 101
- lower conductor
- 102
- upper conductor
- 103
- movable conductor
- 104
- movable-side contact
- 105
- fixed-side contact
- 106
- flexible conductor
- 107
- opening spring
- 108
- arc extinguishing chamber
- 110
- circuit breaker
- 200, 300
- electromagnetic actuator
Claims (19)
- An electromagnetic actuator comprising:a tubular coil generating a magnetic flux in an axial direction thereof when a current flows therethrough;a movable core installed in a state where the movable core can reciprocate in the axial direction of the coil;a shaft surrounded by the movable core, operating an opening/closing operation between a movable-side contact and a fixed-side contact of a circuit breaker, and movable together with the movable core;a tubular yoke pipe surrounding the coil;a fixed-side lid plate disposed at one end of the yoke pipe in the axial direction of the coil;a movable-side lid plate disposed at another end of the yoke pipe in the axial direction of the coil;a fixed core disposed on an inner circumferential side of the coil from the fixed-side lid plate in a direction toward the movable-side lid plate; anda tubular yoke projection portion projecting on the inner circumferential side of the coil from the movable-side lid plate in a direction toward the fixed-side lid plate so as to face the fixed core, whereinthe movable core is disposed in a space on an inner circumferential side of the yoke projection portion, andwhen the movable core is excited by a current flowing through the coil, the movable core moves together with the shaft from an initial position in a direction toward the fixed core in the axial direction of the coil to bring the movable-side contact and the fixed-side contact into contact with each other to stop movement of the shaft, and then moves relative to the shaft to a position at which the movable core comes into contact with the fixed core in an excitation operation completion state.
- The electromagnetic actuator according to claim 1, wherein a contact surface at which the movable core and the fixed core come into contact with each other in the excitation operation completion state is located on the movable core moving direction side with respect to a center position of the coil in the axial direction of the coil.
- The electromagnetic actuator according to claim 1 or 2, wherein, in the axial direction of the coil, a length of the movable core is longer than 1/2 of a length of the yoke pipe.
- The electromagnetic actuator according to any one of claims 1 to 3, wherein, in the shaft, a shaft protrusion portion having a larger outer diameter than a portion, of the shaft, which is inserted into the movable core is provided at an end portion position on the fixed-side lid plate side of the movable core.
- The electromagnetic actuator according to claim 4, wherein a fixed core recess which is recessed so as to house the shaft is formed on a fixed core end surface which is an end surface, of the fixed core, facing the movable core.
- The electromagnetic actuator according to claim 5, whereina fixed core step portion is formed so as to be stepped on an inner wall surface of the fixed core recess and face the shaft protrusion portion, andin the excitation operation completion state, the shaft protrusion portion is surrounded by the fixed core recess so as to be housed in the fixed core recess, and there is a gap between the shaft protrusion portion and the fixed core step portion.
- The electromagnetic actuator according to claim 5 or 6, whereina return spring is disposed between the shaft protrusion portion and the fixed core recess, andthe shaft and the fixed core are connected via the return spring.
- The electromagnetic actuator according to any one of claims 1 to 7, whereina contact-pressure spring is disposed between the movable core and the shaft, andthe movable core and the shaft are connected via the contact-pressure spring.
- The electromagnetic actuator according to any one of claims 1 to 8, wherein, between the movable core and the shaft, a first movable core bearing which supports the movable core such that the movable core is movable relative to the shaft, is provided on the shaft at the end portion position on the fixed-side lid plate side of the movable core.
- The electromagnetic actuator according to any one of claims 1 to 9, wherein, between the movable core and the shaft, a second movable core bearing which supports the movable core such that the second movable core bearing is movable together with the movable core relative to the shaft, is provided at an end portion position on the movable-side lid plate side of the movable core.
- The electromagnetic actuator according to any one of claims 1 to 10, whereinthe shaft hasa first shaft end portion which is one end portion penetrating the fixed-side lid plate, anda second shaft end portion which is another end portion penetrating the movable-side lid plate, andthe second shaft end portion is formed such that an outer diameter thereof is larger than that of the portion, of the shaft, which is inserted into the movable core.
- The electromagnetic actuator according to claim 11, whereina first shaft bearing which supports movement of the shaft is provided between the fixed-side lid plate and the first shaft end portion, anda second shaft bearing which supports movement of the shaft is provided between the movable-side lid plate and the second shaft end portion.
- The electromagnetic actuator according to any one of claims 1 to 12, wherein the yoke projection portion hasa yoke main projection portion disposed on the movable-side lid plate side, anda yoke narrow projection portion extending from the yoke main projection portion in the direction toward the fixed-side lid plate.
- The electromagnetic actuator according to any one of claims 1 to 13, whereinthe fixed core hasa fixed core base portion disposed on the fixed-side lid plate side, anda fixed core narrow projection portion extending from the fixed core base portion in the direction toward the movable-side lid plate,the fixed core base portion has the fixed core end surface which is the end surface facing the movable core, andthe fixed core narrow projection portion has a tubular shape which surrounds a movable core distal end portion which is a distal end portion of the movable core in a direction in which the movable core moves toward the fixed core base portion.
- The electromagnetic actuator according to any one of claims 1 to 14 wherein, in the movable-side lid plate, an air outlet is provided at a portion surrounded by the yoke projection portion, so as to penetrate the movable-side lid plate.
- The electromagnetic actuator according to claim 15, wherein an airtight bearing which supports movement of the movable core relative to the yoke projection portion and blocks outflow of air is provided between the movable core and the yoke projection portion.
- The electromagnetic actuator according to claim 16, wherein a plurality of the airtight bearings are provided.
- The electromagnetic actuator according to any one of claims 15 to 17, wherein a spring pressing plate which closes a gap between the movable core and the shaft such that air inside the movable core does not leak, is provided.
- A circuit breaker in which the electromagnetic actuator according to any one of claims 1 to 18 is used for operating an opening/closing operation between the movable-side contact and the fixed-side contact.
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
PCT/JP2020/014854 WO2021199296A1 (en) | 2020-03-31 | 2020-03-31 | Electromagnetic actuator and circuit breaker using same electromagnetic actuator |
Publications (2)
Publication Number | Publication Date |
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EP4131295A1 true EP4131295A1 (en) | 2023-02-08 |
EP4131295A4 EP4131295A4 (en) | 2023-05-17 |
Family
ID=77928032
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP20928867.9A Pending EP4131295A4 (en) | 2020-03-31 | 2020-03-31 | Electromagnetic actuator and circuit breaker using same electromagnetic actuator |
Country Status (3)
Country | Link |
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EP (1) | EP4131295A4 (en) |
JP (1) | JP7361889B2 (en) |
WO (1) | WO2021199296A1 (en) |
Family Cites Families (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPH09199320A (en) | 1996-01-16 | 1997-07-31 | Mitsubishi Electric Corp | Electromagnetic solenoid |
JP2003163115A (en) | 2001-11-27 | 2003-06-06 | Shindengen Electric Mfg Co Ltd | Electromagnetic actuator |
JP4437190B2 (en) | 2003-11-05 | 2010-03-24 | 新電元メカトロニクス株式会社 | solenoid |
JP5727862B2 (en) * | 2011-05-19 | 2015-06-03 | 富士電機機器制御株式会社 | Magnetic contactor |
KR101943366B1 (en) * | 2015-12-30 | 2019-01-29 | 엘에스산전 주식회사 | Direct Relay |
JP7103091B2 (en) * | 2018-09-07 | 2022-07-20 | オムロン株式会社 | relay |
-
2020
- 2020-03-31 EP EP20928867.9A patent/EP4131295A4/en active Pending
- 2020-03-31 WO PCT/JP2020/014854 patent/WO2021199296A1/en unknown
- 2020-03-31 JP JP2022513006A patent/JP7361889B2/en active Active
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WO2021199296A1 (en) | 2021-10-07 |
JP7361889B2 (en) | 2023-10-16 |
JPWO2021199296A1 (en) | 2021-10-07 |
EP4131295A4 (en) | 2023-05-17 |
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