JP2002289430A - Electromagnet and switchgear operating mechanism using it - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve the problem raised by a conventional electromagnet which maintains an attracting state by using a permanent magnet that the permanent magnet has the possibility of being degaussed, because the magnet exists in a magnetic path formed by a coil current and is directly reversely excited when the electromagnet is demagnetized. SOLUTION: The electromagnet 10 is constituted of a coil 3, a movable core 1 which moves on the center axis of the coil 3, and a fixed core 2 which is provided to cover the top face, bottom face, and outer peripheral surface of the coil 3. In the electromagnet 10, the permanent magnet 12 is arranged in a void surrounded by the movable core 1 and fixed core 2 so that the movable core 1 is attracted to the fixed core 2 by means of a magnetic field generated by the permanent magnet 12.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electromagnet and a configuration of an operation mechanism of a switchgear using the same, and more particularly to an electromagnet in which permanent magnets are suppressed from being demagnetized and a highly reliable switchgear to which the electromagnet is applied. Related to the operation mechanism.

[0002]

2. Description of the Related Art An operation mechanism of a switchgear includes an electric spring operation mechanism, a hydraulic and pneumatic operation mechanism, and the like. Usually, these operation mechanisms have a relatively high manufacturing cost due to a large number of parts and a complicated link mechanism. One of the techniques for simplifying the link mechanism is an operation mechanism using an electromagnet. For example, in a vacuum contactor described in Japanese Patent Application Laid-Open No. 5-234475, an electromagnet is used for a closing operation, and is charged simultaneously with closing. Release the cut-off spring to open the contacts.
Further, in the operating mechanism described in JP-T-10-505940, a plunger that penetrates two coils for closing and closing is provided, and both closing and closing operations are performed by an electromagnet. Further, in Japanese Patent Application Laid-Open No. 2000-249092, the closed state is maintained by using the attractive force of the permanent magnet,
The reverse operation is performed by the coil current, and the breaking operation is performed by the movable member driving spring provided separately. In this case, there is an advantage that a single coil can be used regardless of whether the coil is for closing or for closing.

[0003]

However, the conventional electromagnet with a permanent magnet has the following disadvantages. For permanent magnets,
There are rare earth samarium-cobalt magnets, neodymium magnets, alnico magnets, and ferrite magnets. If a neodymium-based magnet having a high residual magnetic flux density and a relatively low cost is used, the electromagnet can be made small and inexpensive. However, neodymium magnets have a holding force of 1000 kA.
/ M, and the magnetizing magnetic field needs to be 2000 kA / m (corresponding to a magnetic flux density of 2.5 T) or more. Therefore, it is practically impossible to magnetize the permanent magnet with the coil of the built-in electromagnet, and the magnet after magnetizing must be built.

When an electromagnet is applied to an operation mechanism of a switchgear, it is necessary to satisfy a long-term operation guarantee of 20 years or more and a large number of operations of 10,000 times or more. Therefore, factors that demagnetize the permanent magnet must be eliminated as much as possible. In the electromagnet with a permanent magnet described in JP-A-2000-249092, a blocking operation is performed by applying a reverse magnetic field directly to the permanent magnet. By repeatedly applying the reverse energy to the permanent magnet, there is a risk of demagnetization, that is, shortening the life.

Further, if a permanent magnet exists in the magnetic path,
The magnetic resistance seen from the coil increases. Since the magnetic permeability of the permanent magnet is almost the same as that of air, at the start of the operation, there is a gap obtained by adding the thickness of the permanent magnet to the stroke length, and a larger ampere turn is required.

In addition, dimensional errors that occur during the manufacturing stage are unavoidable in the thickness and iron core of the permanent magnet.
The gap at the end of the stroke between the permanent magnet and the movable iron core that moves forward and backward changes. The gap changes the closing characteristics, the blocking characteristics, and the closing state holding force (suction force). However, if the tolerance of the dimensional error, that is, the tolerance is strictly controlled in order to stabilize the characteristics,
It becomes a bottleneck for the production of inexpensive electromagnets.

The present invention has been conceived as a means for solving the above-mentioned problems, and has as its object the advantage that the permanent magnet is not directly reverse-excited and that the permanent magnet does not exist in the magnetic path created by the coil current. An object of the present invention is to provide an electromagnet having a long life and high efficiency, and an operation mechanism of a switchgear using the electromagnet. Another object of the present invention is to provide an electromagnet in which it is easy to adjust the distance between a permanent magnet and a movable core that moves forward and backward in opposition to the permanent magnet.

[0008]

That is, the present invention provides a coil 3 and a movable iron core 1 moving on the center axis of the coil 3.
And a permanent magnet 12 disposed in a gap surrounded by the movable core 1 and the fixed core 2 in an electromagnet including a fixed core 2 provided so as to cover an upper surface, a lower surface, and an outer peripheral surface of the coil 3. The electromagnet 10 causes the movable iron core 1 to be attracted to the fixed iron core 2 by a magnetic field generated by the permanent magnet 12.

Further, the present invention comprises a coil 3, a movable core 1 moving on the center axis of the coil 3, and a fixed core 2 provided so as to cover the upper, lower, and outer peripheral surfaces of the coil 3. In the electromagnet to be provided, a protrusion 4 made of a magnetic material is provided on the fixed iron core 2 on the side where the movable iron core 1 is inserted, and the movable iron core 1 is constituted by a plunger 5 and a steel plate 6 fixed to an end thereof. 5 and the fixed iron core 2, the steel plate 6 and the protrusion 4 are configured to face each other in the same direction, and are surrounded by the plunger 5, the protrusion 4, the steel plate 6, and the fixed core 2. The electromagnet 10 is provided with a permanent magnet 12 in the region shown.

The present invention further provides a coil 3, a movable core 1 moving on a center axis of the coil 3,
An electromagnet comprising a fixed core 2 provided so as to cover the upper surface, the lower surface, and the outer peripheral surface of the fixed core 2, a protrusion 4 of a magnetic material is provided on a side of the fixed core 2 where the movable core 1 is inserted;
The movable iron core 1 is composed of a plunger 5 and a steel plate 6 fixed to an end thereof. A permanent magnet 12 is arranged in a gap surrounded by the plunger 5, the projecting portion 4, the steel plate 6, and the fixed iron core 2. An electromagnet 10 configured such that the side surface of the steel plate 6 and the protruding portion 4 face each other, and the end surface of the plunger 5 and the fixed core 2, and the steel plate 6 and the permanent magnet face each other in the same direction. is there.

Further, the present invention provides the above-mentioned electromagnet,
A power supply circuit capable of selectively flowing forward and reverse currents through the coil 3, generating a magnetic field in the same direction as the magnetic field generated by the permanent magnet 12 when a forward current flows, and attracting the coil 3 The operation is to perform the release operation by canceling the magnetic field generated by the permanent magnet 12 when a current flows in the reverse direction.

Further, the present invention provides a coil, a movable iron core moving on a center axis of the coil, a fixed iron core provided on both end surfaces and an outer peripheral surface of the coil in the axial direction, and a forward and a reverse direction on the coil. And a power supply capable of flowing an electric current to the coil, the electromagnet moving the movable core toward the fixed core when the coil is forwardly energized, wherein the fixed core is disposed in the axial direction of the coil. A fixed core upper member provided so as to cover one end surface, a permanent magnet is disposed on an upper surface of the fixed core upper member, and the movable iron core includes the fixed core upper member sandwiching the permanent magnet. And a plunger member having a cylindrical surface facing the inner peripheral surface of the coil.

It is preferable that a distance g1 between the inner peripheral surface of the fixed core upper member and the cylindrical surface of the plunger member is smaller than the axial thickness t of the permanent magnet.

[0014] A magnetic member may be interposed between the plate member side end surface of the plunger member and the plate member.

The permanent magnet may be selected from permanent magnets including rare earth samarium-cobalt magnets, neodymium magnets, alnico magnets, and ferrite magnets.

Further, the present invention comprises the above-mentioned electromagnet, a contact which can be freely connected and detached, and a breaking spring for opening the contact, and selects a forward and a reverse current for the coil 3 of the electromagnet. A power supply circuit capable of flowing current is provided, and when a current is passed in the forward direction, the contact is turned on while accumulating the cut-off spring, and the energized state is maintained by the attraction force of the permanent magnet 12. This is an operation mechanism of an opening / closing device that cancels a magnetic flux generated by the permanent magnet 12 when a current flows in a reverse direction, and shuts off with a force of the shutoff spring.

It is desirable that a plurality of the same electromagnets are used in combination according to the capacity of the switchgear.

That is, with the electromagnet configured as described above, a magnetic field generated by applying a current to the coil in the opposite direction during the cutting operation does not penetrate the permanent magnet, so that the permanent magnet is not directly reverse-excited. In addition, since there is no permanent magnet in the magnetic path created by the coil current, there is no need to demagnetize the permanent magnet, and it is also possible to use a neodymium-based permanent magnet. Can be provided.

Further, by interposing a magnetic member between the flat member side end surface of the plunger member and the flat member, the thickness of the magnetic member is changed, or the magnetic member is formed of a thin plate. By changing the number of thin plate members, the gap at the stroke end of the movable core between the permanent magnet and the movable core that moves forward and backward can be easily adjusted. In other words, the characteristics can be stabilized without making the tolerances of the parts strict, and an inexpensive and highly reliable electromagnet can be provided. Further, by applying the operation mechanism of the switch to the electromagnet, a small, inexpensive and highly reliable switch can be realized.

[0020]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described with reference to FIGS.

(Embodiment 1) A first embodiment of the present invention will be described with reference to FIGS.

FIG. 1 shows an electromagnet 10 according to an embodiment of the present invention.
FIG. The electromagnet 10 has an axially symmetric structure, and a symbol for explaining the structure is added to the right half of the figure, and a magnetic field B (chain line) generated by a current flowing through the permanent magnet 12 and the coil 3 is shown in the left half.

The movable iron core 1 is composed of a plunger 5 penetrating on the center axis of the coil 3 and a disk-shaped steel plate 6 fixed to an end thereof, and a non-magnetic connecting member 7 fixed to an end of the plunger 5. To the load W. The load W exerts a force for driving the movable iron core 1 in the upward direction while the electromagnet 10 is attracted. The fixed iron core 2 includes a steel pipe 2 a, a convex steel material 2 b, and a ring-shaped steel plate 2 which are all magnetic materials.
c. Convex steel 2b and ring-shaped steel plate 2c
May be attached by screwing from both ends of the steel pipe 2a as shown, or may be fixed by welding. Further, the steel pipe 2a and the convex steel material 2b or the steel pipe 2a
The ring-shaped steel plate 2c may be manufactured by cutting from a columnar material. Here, the steel material 2b has a convex shape, but may be a simple flat plate. However, it is known that providing the gap X between the end face of the plunger 5 and the fixed iron core 2 near the center of the coil 3 reduces the leakage magnetic flux, and it is better to use a convex steel material. Further, the convex steel material 2b may be manufactured as a single body, or may be configured by connecting two steel plates. The coil 3 includes a bobbin 3a made of an insulating material or a non-magnetic metal (aluminum, copper, or the like), and a winding 3b.

The ring-shaped steel plate 2c is screwed relatively deeply into the steel pipe 2a to provide a magnetic material projection 4. The electromagnet 10 of this embodiment has a structure in which the end face of the plunger 5, the convex steel material 2b, the disk-shaped steel plate 6, and the protruding portion 4 are respectively opposed in the same direction. The distance g between the side surface of the plunger 5 and the ring-shaped steel plate 2c was shorter than the stroke length of the movable iron core. The reason will be described later.
The distance X between the end face of the plunger 5 and the convex steel material 2b
Is shorter than the distance L between the disk-shaped steel plate 6 and the protruding portion 4, and when the suction operation is completed, the plunger 5 comes into contact with the convex steel material 2b.

The ring-shaped permanent magnet 12 is arranged in a region surrounded by the plunger 5, the disk-shaped steel plate 6, the protrusion 4, and the ring-shaped steel plate 2c, and is fixed on the ring-shaped steel plate 2c. . Reference numeral 13 denotes a metal fitting for the permanent magnet 12 made of a non-magnetic material such as SUS, for example, and the metal fitting 13 is fixed by being screwed into the steel pipe 2a. A gap is provided between the permanent magnet 12 and the protruding portion 4 by the holding metal 13, in order to prevent the magnetic flux generated by the permanent magnet 12 from being short-circuited by the protruding portion 4.

FIG. 2 shows the operation of the electromagnet 10 of the present invention.
This will be described with reference to FIG. 2 illustrates a state immediately after the start of the suction operation, FIG. 3 illustrates a state immediately before the completion of the suction operation, FIG. 4 illustrates a state after the completion of the suction operation, and FIG. 5 illustrates a state during the release operation.

When the coil 3 is energized by an external power supply circuit (not shown), an attractive force F0 acts on the end face of the plunger 5, and the movable iron core 1 starts operating downward. Here, the distance g between the side surface of the plunger 5 and the ring-shaped steel plate 2c is:
Since the stroke length is set shorter than the movable core 1, the magnetic field Bc generated by the coil current passes through the path O1. Here, the direction of the coil current and the polarity of the permanent magnet 12 need to be set in advance so that the direction of the magnetic field Bc and the direction of the magnetic field Bm generated by the permanent magnet 12 become the direction of the arrow in FIG. The directions of the magnetic field Bc and the magnetic field Bm may be simultaneously opposite.

When the movable iron core 1 is driven by the suction force F0, the state shown in FIG. As the movable iron core 1 moves, the gap L between the disk-shaped steel plate 6 and the protruding portion 4 decreases, and becomes shorter than the gap g between the plunger 5 and the ring-shaped steel plate 2c (g> L). Therefore, the magnetic field Bc due to the coil current starts to diverge to the path O2, and most of the magnetic field Bc flows through the path O2 when the operation is completed. That is, with the movement of the movable iron core 1, in addition to the suction force F 0 acting on the end face of the plunger 5, the suction force F 1 also acts between the disk-shaped steel plate 6 and the protrusion 4. In the state immediately before the completion of the attraction operation, the attraction force F0 is further increased because the magnetic field Bm of the permanent magnet 12 passes through the path O3.

After the operation of the movable iron core 1 is completed, the coil 3
Is turned off, the attracted state of the permanent magnet 12 keeps the attracted state. Even after the suction operation is completed, the magnetic field Bm generated by the permanent magnet 12 passes through the path O3 because there is a gap between the disk-shaped steel plate 6 and the protruding portion 4. By the suction force F0,
The attracted state of the movable core 1 and the fixed core 2 is maintained.

The release operation will be described with reference to FIG.
The release operation is performed by applying a current to the coil 3 in a direction opposite to that during the suction operation. The magnetic field Bc generated by the coil current flows through the path O2, and cancels the magnetic field Bm generated by the permanent magnet 12. The suction force F0 acting on the end face of the plunger 5 is reduced, and the movable iron core 1 moves upward by the load force. However, the magnetic field Bc
As a result, the attractive force Fr acts simultaneously between the disk-shaped steel plate 6 and the protruding portion 4, so that when an excessive current is applied to the coil 3, the attractive operation may be performed again. It is necessary to provide a means for limiting the coil current in accordance with the balance with the load force and for interrupting the coil current immediately after the release operation is completed.

Next, the effect of this embodiment will be described.
In the conventional electromagnet with a permanent magnet, the permanent magnet 12 is present in the magnetic path created by the coil current, and thus the permanent magnet 12 is directly reverse-excited during the release operation. If the permanent energy is continuously applied to the permanent magnet 12 by the repetitive operation, there is a risk of demagnetization. In the electromagnet of the present embodiment, the permanent magnet 12 is disposed in the gap surrounded by the movable iron core 1 and the fixed iron core 2, that is, in the magnetically shielded region, so that the magnetic field Bc generated by the coil current directly acts on the permanent magnet 12. Never. In the release operation, no reverse energy is applied to the permanent magnet 12. The risk of demagnetization is avoided, and the electromagnet has a long life and high reliability.

The magnetic permeability of the permanent magnet 12 is substantially the same as that of air. If the permanent magnet 12 is present in the magnetic path created by the coil current, the magnetic resistance seen from the coil increases. At the start of the operation, there is a gap corresponding to the thickness of the permanent magnet 12 added to the stroke, and the ampere turn required for the operation increases. In the electromagnet 10 according to the present embodiment, the permanent magnet is not present in the magnetic path created by the coil current, so that the magnetic resistance is small and the efficiency is high.

(Embodiment 2) A second embodiment of the present invention will be described with reference to FIGS.

FIG. 6 is a sectional view of an electromagnet 10 according to an embodiment of the present invention. The movable iron core 1 is composed of a plunger 5 penetrating on the center axis of the coil 3 and a disk-shaped steel plate 6 fixed to an end of the plunger 5. Connecting. The fixed iron core 2 is composed of a steel pipe 2a, a convex steel material 2b, and a ring-shaped steel plate 2c, all of which are magnetic materials. The convex steel material 2b and the ring-shaped steel plate 2c may be attached by screwing from both ends of the steel pipe 2a as shown in the figure, or may be fixed by welding. The convex steel material 2b may be manufactured as a single piece, or may be configured by connecting two steel plates. The coil 3 includes a bobbin 3a made of an insulating material or a non-magnetic metal (aluminum, copper, or the like), and a winding 3b.

The ring-shaped permanent magnet 12 is fixed on the ring-shaped steel plate 2c. Reference numeral 15 denotes a pipe made of a non-magnetic member such as SUS, for example, and is fixed to the steel pipe 2a while holding the permanent magnet 12. Since a large force is not applied to the pipe 15, the pipe 15 may be fixed with a screw 16 or the like. The reason why the pipe 15 is made of a non-magnetic member is to prevent the magnetic field of the permanent magnet 12 from being short-circuited by the pipe 15. Further, a lid 17 made of a non-magnetic member is attached to an end of the pipe 15, and a rod 8 fixed to the movable core 1 penetrates. The lid 17, the convex steel member 2 b, the connecting member 7, and the rod 8 prevent the movable core 1 from being misaligned.

The distance X between the end face of the plunger 5 and the convex steel material 2b is shorter than the distance L between the disk-shaped steel plate 6 and the permanent magnet 12, and the disk-shaped steel plate 6 collides and the permanent magnet Avoid breaking 12.

FIG. 6 shows the operation of the electromagnet 10 of the present invention.
This will be described with reference to FIG. 6 to 9 show cross sections of the electromagnet 10, in which reference numerals for explaining the structure are added to the right half, and the state of the magnetic field is added to the left half.

FIG. 6 shows a state immediately after the start of the suction operation.
The distance X between the end face of the plunger 5 and the convex steel material 2b and the distance L between the disk-shaped steel plate 6 and the permanent magnet 12 are both the same.
The magnetic field Bm generated by the permanent magnet 12 is longer than the distance g between the plunger 2 and the plunger 5 and extends only around the permanent magnet 12 as shown in FIG. Therefore, the driving force acting on the movable iron core 1 is very weak. When the coil 3 is energized from an external power supply circuit (not shown), an attractive force F0 acts on the end face of the plunger 5 due to the magnetic field Bc caused by the coil current, and the movable iron core 1 starts operating downward. Here, since the distance g between the side surface of the plunger 5 and the ring-shaped steel plate 2c is set shorter than the stroke length of the movable iron core 1, the magnetic flux Bc generated by the coil current passes through the path O4. The direction of the coil current and the polarity of the permanent magnet 12 need to be set in advance so that the direction of the magnetic field Bc due to the coil current and the direction of the magnetic field Bm of the permanent magnet 12 become the directions of the arrows shown in FIG. The directions of the magnetic field Bc and the magnetic field Bm may be simultaneously reversed.

When the movable iron core 1 is driven by the suction force F0, the state shown in FIG. The gap L between the disk-shaped steel plate 6 and the permanent magnet 12 decreases with the movement of the movable iron core 1 and becomes shorter than the gap g between the plunger 5 and the ring-shaped steel plate 2c (g> L). Magnet 12
Passes through the path O5. That is, as the movement of the movable iron core 1 progresses, the attractive force F0 acting on the end face of the plunger 5 and the attractive force F1 also act between the disk-shaped steel plate 6 and the permanent magnet 12. Further, since the magnetic field Bm of the permanent magnet 12 passes through the opposing surfaces of the plunger 5 and the convex steel material 2b, the attraction force F0 is further increased.

After the operation of the movable iron core 1 is completed, the coil 3
, The attractive force F0 and the attractive force F1 are actuated by the magnetic flux Bm of the permanent magnet 12, and this state is maintained.

On the other hand, as shown in FIG. 8, the release operation is performed by supplying a current to the coil 3 in a direction opposite to that during the suction operation. The magnetic field Bc generated by the coil current flows through the path O6, and the permanent magnet 1
2 cancels the magnetic field Bm created. The suction force F0 decreases, and the movable iron core 1 moves upward by the load force.

The effect of this embodiment will be described. Similarly to the electromagnet of the first embodiment, the magnetic field Bc generated by the coil current does not directly act on the permanent magnet 12, and does not give reverse energy during the release operation. Therefore, the danger of permanent magnet demagnetization is avoided, and the electromagnet has a long life and high reliability. Also,
The magnetic permeability of the permanent magnet 12 is almost the same as that of air, and if the permanent magnet 12 is present in the magnetic path created by the coil current, the magnetic resistance viewed from the coil increases. At the start of the operation, there is a gap corresponding to the thickness obtained by adding the thickness of the permanent magnet 12 to the stroke, and the required ampere-turn increases. In the electromagnet 10 according to the present embodiment, the permanent magnet is not present in the magnetic path created by the coil current, so that the magnetic resistance is small and the efficiency is high.

Further, the electromagnet of this embodiment has the following effects. In the release operation, in the electromagnet of the first embodiment, the magnetic field Bm generated by the coil current causes the attractive force F1 to act between the disk-shaped steel plate 6 and the magnetic body projecting portion 4, so that when an excessive current is applied to the coil 3, the electromagnet of the first embodiment is again activated. There was a possibility of a suction operation. Therefore, it is necessary to provide a means for limiting the coil current based on the balance with the load force and for immediately interrupting the coil current after the release operation is completed. However, in the electromagnet of the present embodiment, there is no portion that generates an attractive force by the magnetic field Bc due to the coil current, and the attractive operation is not performed again. Therefore, it is not necessary to limit the coil current in accordance with the balance with the load force and to provide a means for interrupting the coil current immediately after the release operation is completed.

(Embodiment 3) A third embodiment of the present invention will be described with reference to FIG. 9 (on state) and FIG. 10 (off state). 9 and 10 show an electromagnet 10 according to an embodiment of the present invention.
9 is a cross-sectional view of the electromagnet when the switchgear is turned on when coupled to the switchgear, and FIG. 10 illustrates the electromagnet when the switchgear is off when coupled to the switchgear. In the following description, the on state and the off state are both
When the electromagnet is connected to the switchgear, the state of the electromagnet when the switchgear is in an on state or an off state.

The coil 3 comprises a bobbin 3a made of an insulator or a non-magnetic metal (aluminum, copper, etc.)
b.

The illustrated electromagnet 10 includes a coil 3, a movable iron core made of a magnetic material moving on the central axis of the coil 3, and a magnetic material provided so as to cover both axial end surfaces and the outer peripheral surface of the coil 3. And a power source (not shown) capable of flowing a current through the coil 3 in a forward direction and a reverse direction. When the coil 3 is energized in the forward direction, the movable core is moved in the direction toward the fixed core, that is, from right to left in the drawing. In the following description, for convenience, the right side of FIG. 9 is indicated by the upper side, and the left side is indicated by the lower side.

The fixed iron core is provided so as to cover one end face in the axial direction of the coil 3, and is a rectangular flat plate 2 d which is a fixed iron core upper member having a circular opening concentric with the coil 3 in the center portion. A rectangular flat plate 2f, which is a fixed iron core lower member having a circular opening concentric with the coil 3 in the center and provided so as to cover the other end surface in the axial direction of the coil, and between the rectangular flat plate 2d and the rectangular flat plate 2f And a cylinder 2g disposed on the upper surface of the rectangular flat plate 2f and concentrically with the steel tube 2e. Square flat plate 2d, square flat plate 2f,
The steel pipe 2e and the cylinder 2g are all magnetic bodies, and the rectangular flat plate 2f and the cylinder 2g are fixed with screws or the like or welded together. Of course, it may be cut out from one material.

A disk-shaped permanent magnet 12 having an opening at the center is attracted and arranged on the upper surface of the rectangular flat plate 2d, and is fixed by an adhesive. The permanent magnet 12 is neodymium-based,
Any of samarium-based, alnico-based, neodymium-bonded, and ferrite-based materials may be used. Although the illustrated permanent magnet 12 is a single annular magnet, it is not necessarily required to form a continuous annular shape. May be arranged on the upper surface of the. However, also in this case, it is necessary to make the area of the surface facing the cylindrical flat plate 6a described later to be an area capable of exhibiting a required suction force.

The movable iron core includes the opening of the rectangular flat plate 2d, the opening of the rectangular flat plate 2f, the steel pipe 2e, and the cylinder 2
g through a center, a non-magnetic rod 19, a plunger 5 which is a cylindrical magnetic body fitted and fixed to the rod 19, and a thin plate 21 which is a magnetic member on the upper side of the plunger 5. And a cylindrical flat plate 6 a which is a magnetic material and is fixed to the rod 19. The lower surface of the cylindrical flat plate 6a faces the upper surface of the rectangular flat plate 2d with the permanent magnet 12 interposed therebetween, and the outer peripheral surface of the plunger 5 faces the inner peripheral surface of the coil 3. That is, the outer diameter of the plunger 5 is smaller than any of the inner diameter of the coil 3, the diameter of the central opening of the permanent magnet 12, and the diameter of the central opening of the rectangular flat plate 2d, and the inside of the plunger 5 moves in the axial direction. Although it is possible, cylindrical flat plate 6
The outer diameter of “a” is larger than the diameter of the central opening of the permanent magnet 12, and the cylindrical flat plate 6 a cannot pass through the central opening of the permanent magnet 12. The plunger 5 and the cylindrical flat plate 6a are fixed to the rod 19 by screwing or a stopper.

The central opening of the permanent magnet 12 and the central opening of the rectangular flat plate 2d are concentric and have the same diameter, and the thickness t of the permanent magnet 12 in the axial direction is the inner circumference of the central opening of the rectangular flat plate 2d. The distance g1 between the surface and the outer peripheral surface of the plunger 5 is larger than g1.

The outer diameter of the cylinder 2g is smaller than the inner diameter of the coil 3 and is equal to the outer diameter of the plunger 5.
The inner diameter of the cylinder 2g is set to a size that allows the rod 19 to pass freely. That is, the lower surface of the plunger 5 is opposed to the upper surface of the cylinder 2g, and when the movable iron core moves leftward in the axial direction, the limit of the movement is determined by the point at which the lower surface of the plunger 5 and the upper surface of the cylinder 2g abut. .

Above the permanent magnet 12, a tube 15a of a non-magnetic material (stainless steel is used in this embodiment) is arranged concentrically with the coil 3, and the tube 15a is sandwiched between the tube 15a and the permanent magnet 12. The rectangular flat plate 18 to be clamped is disposed. The rectangular flat plate 18 may be a magnetic material or a non-magnetic material. At four corners or two diagonal corners of the rectangular flat plate 2f, the square flat plate 2d, and the rectangular flat plate 18, holes are formed so that a rod 14 which is a non-magnetic material threaded at both ends passes therethrough. The whole is fixed by tightening with a nut.

The rectangular flat plate 18 and the square flat plate 2f have coils
A hole through which the rod 19 passes is formed concentrically with 3, and a bearing or a dry bearing is provided in this hole to reduce friction when the rod 19 slides, thereby achieving maintenance saving.

9 is maintained by the attractive force of the permanent magnet 12 (generated by the magnetic flux φ1). That is,
The on state is the attraction force of the permanent magnet 12, and the state where the gap g3 between the lower surface of the plunger 5 and the upper surface of the cylinder 2g is 0, that is, the state where the lower surface of the plunger 5 is in contact with the upper surface of the cylinder 2g is maintained. . Instead of the lower surface of the plunger 5 directly contacting the upper surface of the cylinder 2g, a thin non-magnetic material may be interposed therebetween.

When assembling the electromagnet, a plurality of thin plates 2 having the same thickness
1 is prepared, and the number of the thin plates 21 sandwiched between the plunger 5 and the cylindrical flat plate 6a is changed, so that a gap g2 of a desired size is formed between the permanent magnet 12 and the cylindrical flat plate 6a in the state of FIG. Is formed. The reason for forming the gap g2 is that the cylindrical plate 6a
This is because, when a collision occurs, the permanent magnet 12 is demagnetized, and the life of the permanent magnet 12 is shortened.

Further, by changing the number of the thin plates 21 to make the gap g2 in the inserted state as close to 0 as possible, it is possible to reduce the magnetic resistance and increase the attractive force. As a result, the conventional attractive force can be secured even if the volume of the permanent magnet 12 is reduced by reducing the thickness of the permanent magnet or reducing the surface area adsorbed on the rectangular flat plate 2d. Therefore, the cost of the permanent magnet which largely depends on the volume is reduced, and a small and inexpensive electromagnet can be obtained. Also, by changing the number of the thin plates 21, the value of the gap g2 in the on state can be made close to a desired constant value, so that the attraction force of the permanent magnet in the on state and the on / off operation characteristics can be stabilized. Thus, the reliability of the electromagnet can be improved.

Instead of adjusting the value of the air gap by using a plurality of thin plates having the same thickness, plates of various thicknesses having slightly different thicknesses are prepared, and one having an appropriate thickness among them is prepared. To
The value of the gap may be adjusted by using one sheet or a combination of different thicknesses.

Next, FIG. 11 (at the time of the ON operation) and FIG. 12 (at the time of the OFF operation)
The ON / OFF operation will be described with reference to FIG.

At the time of the ON operation shown in FIG. 11, a current is supplied from a power source (not shown) to the coil 3 so as to generate a magnetic field in the same direction as the magnetic field generated by the permanent magnet 12 (forward current). Magnetic fluxes φ2 and φ1 shown in FIG. 11 are generated by the coil current and the permanent magnet 12, respectively, and an attractive force for moving the cylindrical flat plate 6a to the left in the drawing, that is, a force for attracting the movable core to the fixed core is generated. This attractive force is generated both in the gap between the plunger 5 and the cylinder 2g and in the gap between the cylindrical flat plate 6a and the permanent magnet 12. The force generated in the gap between the cylindrical flat plate 6a and the permanent magnet 12 is F1, and the force generated in the gap between the plunger 5 and the cylinder 2g is F2. F2 at the time of ON operation is
This is a force generated by the magnetic flux obtained by combining the magnetic flux φ2 and the magnetic flux φ1.

At the time of the turning-off operation shown in FIG. 12, a current in the opposite direction to that at the time of the turning-on operation is supplied to the coil 3 from the power source (not shown). When the on state is maintained, the magnetic flux φ1 formed by the permanent magnet
The sum of the force F1 generated in the gap between the cylindrical flat plate 6a and the permanent magnet 12 and the force F2a generated in the gap between the plunger 5 and the cylinder 2g due to the magnetic flux φ1 is applied to the rod 19 by a cut-off spring (not shown). It is larger than the force F0 applied in the right direction in the figure. That is, the permanent magnet 12
Force overcomes the force of the shut-off spring, and the on state is maintained. In this state, when the current in the opposite direction is passed through the coil 3, the current causes the magnetic flux φ5
Is formed, and the magnetic flux φ1 of the permanent magnet 12 is weakened by the magnetic flux φ5. The plunger 5 and the cylinder 2 are moved by the weakened magnetic flux (or the magnetic flux in the opposite direction to the magnetic flux φ1).
Force F2b is generated in the gap between g. Since F2a> F2b, the leftward force acting on the movable iron core in the drawing decreases, and F0> (F1 + F2b), and the cutting operation is started.

At this time, since the thickness t of the permanent magnet 12 is larger than the distance g1 between the inner peripheral surface of the central opening of the rectangular flat plate 2d and the outer peripheral surface of the plunger 5, it is formed by a reverse current. The magnetic flux φ5 is, as shown in FIG.
Do not pass through 2. This is because the magnetic flux φ5 due to the reverse current has a small magnetic resistance and takes a magnetic path shown in FIG. 12 because the magnetic permeability of the permanent magnet 12 is almost equal to that of air. There is a possibility that demagnetization will occur if the permanent magnet is continuously subjected to reverse excitation.However, in the electromagnet of this embodiment, since the permanent magnet is not subjected to reverse excitation, the possibility of demagnetization is reduced, and a long life is obtained. A highly reliable electromagnet can be obtained.

(Embodiment 4) A fourth embodiment of the present invention will be described with reference to FIGS.

This embodiment is directed to the electromagnet 1 according to the first to third embodiments.
0 is applied to the operation mechanism of the switchgear. FIG.
FIG. 5 is a side sectional view of a three-phase vacuum circuit breaker 20 to which the electromagnet 10 according to the second embodiment is applied. Here, a vacuum circuit breaker will be described as an example, but the electromagnet 10 of the present invention can be applied to another switching device such as a gas circuit breaker. Example 2
An example in which the described electromagnet 10 is applied will be described, but the electromagnet described in Example 1 or Example 3 is also applicable.

The vacuum circuit breaker 20 comprises a vacuum valve 30, an operating mechanism 40, an insulating gantry 31, and an operating space 50 for accommodating the control circuit 51 and the electromagnet 10. The vacuum valves 30 are installed in a state of being arranged in three phases in the depth direction of the paper. The three vacuum valves 30 are connected by a shaft 41 in the operation mechanism 40 and are driven by a single electromagnet 10.

The inside of the vacuum valve 30 is maintained in a vacuum state by a vacuum container comprising upper and lower end plates 32 and an insulating cylinder 33. A fixed contact 37 and a movable contact 38 are arranged in the vacuum valve 30, and closing and closing are realized by the contact and separation thereof. The fixed contact 37 is fixed to the fixed conductor 35 and is electrically connected to the fixed feeder 39. On the other hand, the movable contact 38 is fixed to the movable conductor 36 and connected to the movable feeder 62 via the flexible conductor 61. The bellows 34 has both ends connected to the movable conductor 36 and the end plate 32. The bellows 34 allows the fixed contact 37 and the movable contact 38 to come in contact with and separate from each other while maintaining a vacuum state.

The vacuum valve 30 and the electromagnet 10 are both connected to the shaft 41, and the driving force generated by the electromagnet 10 acts on the movable conductor 36. The movable conductor 36 is electrically insulated from the operating mechanism by the insulating rod 63 and is connected to the lever 42 fixed to the shaft 41. Electromagnet 10
Is connected to the lever 44 by the connecting member 9.

In the closing operation, the contact pressure spring 43 and the blocking spring 4
You must perform 5 energy accumulations at the same time. Contact spring 43
Is a spring for applying contact pressure to the contact at the time of closing,
The blocking spring 45 is a spring for performing a blocking operation.

The contact pressure spring 43 is housed in the insulating rod 63. FIG. 14 shows the structure around the contact pressure spring 43. The contact pressure spring 43 is housed in a contact pressure spring holder 43a molded on the insulating rod 63. The movable conductor 36 is fixed to the connection member 43b, and the connection member 43b is connected to the contact pressure spring holder 43a by the pin 43c. The connection member 43b has a hole slightly larger than the outer diameter of the pin 43c, and the contact pressure spring holder 43a has an elliptical hole 43d. In the closing operation, when the fixed contact 37 and the movable contact 38 come into contact with each other, the pin 43c starts moving in the oval hole 43d (downward in the drawing), and continues to compress the contact pressure spring 43 until the closing operation is completed. On the other hand, the blocking spring 45 is sandwiched between a top plate 46 of the operation mechanism unit 40 and a plate 47 fixed to the connection member 9.
The blocking spring 45 is constantly compressed during the closing operation.

The operation of the switching device 20 will be described. When the coil 3 is energized to generate a magnetic field Bc shown in FIG.
The movable core 1 is driven downward by the attraction force F0, and the movable conductor 36 moves upward accordingly, and the contacts are closed. Even if the current of the coil 3 is cut off after the closing operation is completed, this state is maintained by the attractive force of the permanent magnet 12. In the shutoff operation, when a current in the opposite direction to that of the closing operation is applied to the coil 3, the permanent magnet 12 is turned off as shown in FIG.
Therefore, the movable conductor 36 is driven downward by the force of the cut-off spring 45.

Next, the effect of this embodiment will be described.
By applying the electromagnet 10 according to the first to third embodiments to a switchgear, the permanent magnet 12 used for holding the closed state is not demagnetized, and a long-term warranty of 20 years, and a large number of operations of 10,000 or more can be performed. You will be satisfied. That is, a highly reliable switchgear having a long life can be provided.

In the fourth embodiment, an example in which one electromagnet is used to drive the switchgear has been described. However, a circuit breaker having a large capacity, that is, a large force required for the switching operation is required. Uses a plurality of electromagnets so as to generate a force corresponding to the magnitude of the load. In this case, a reference type electromagnet may be set, and a plurality of reference type electromagnets may be combined so that a required opening / closing operation force can be obtained.

FIGS. 15 and 16 show examples of circuit breakers each using four electromagnets. 15 and FIG.
13, the top plate 46 of the operation mechanism unit 40, the insulating frame 31,
Control circuit 51, fixed side feeder 39, movable side feeder 6
2 corresponds to a plan view in a state in which the electromagnets are removed from the shaft 41. FIG.

In the example shown in FIG. 15, the vacuum valves 30a, 30b, and 30c corresponding to each phase of the three-phase
1 are connected by levers 42a, 42b, 42c, respectively, and have the same type and specifications of electromagnets 10a, 10b, 10c, 1
0d are levers 44a, 44b, 44c, 44, respectively.
It is coupled to the shaft 41 at d. That is, the four electromagnets individually apply a driving force to the shaft 41.

FIG. 16 shows an example in which the vacuum valves 30a, 3
0b, 30c is connected to the shaft 41 as shown in FIG.
15 is different from the example shown in FIG. 15 in the method of coupling the electromagnet to the shaft 41. In FIG. 16, levers 44a and 44b are connected to both ends of a shaft 41, and a connecting rod 52 connecting the levers 44a and 44b is
The levers 44a and 44b are pivotally attached to respective ends. Electromagnets 10a, 10b, 10c, 10d of the same type and specifications
Are connected to the connecting rods 52, respectively.
In this configuration, a driving force is applied to the shaft 41 via the levers 44a and 44b.

In any case, by using a plurality of electromagnets of the same type and the same specification, an opening / closing operation by the plurality of electromagnets can be realized with a simple configuration.

[0076]

According to the electromagnet of the present invention and the operating mechanism of the switchgear using the electromagnet, no reverse excitation is applied to the permanent magnet, so that a small, inexpensive and highly reliable product can be provided. In addition, since the gap between the permanent magnet and the movable iron core that moves forward and backward can be adjusted, a low-cost and highly reliable product can be provided.

[Brief description of the drawings]

FIG. 1 is a sectional view of an electromagnet according to an embodiment of the present invention.

FIG. 2 shows a state immediately after the start of the attraction operation of the electromagnet according to the embodiment of the present invention.

FIG. 3 shows a state immediately before the completion of the attraction operation of the electromagnet according to the embodiment of the present invention.

FIG. 4 shows a state in which the attraction operation of the electromagnet according to the embodiment of the present invention is completed.

FIG. 5 shows a state during a release operation of the electromagnet according to the embodiment of the present invention.

FIG. 6 shows a state immediately after the start of the attraction operation of the electromagnet according to the second embodiment of the present invention.

FIG. 7 shows a state immediately before the completion of the attraction operation of the electromagnet according to the second embodiment of the present invention.

FIG. 8 shows a state during a release operation of an electromagnet according to a second embodiment of the present invention.

FIG. 9 shows an on state of an electromagnet according to a third embodiment of the present invention.

FIG. 10 shows a cut-off state of an electromagnet according to a third embodiment of the present invention.

FIG. 11 shows a state during the on-operation of the electromagnet according to the third embodiment of the present invention.

FIG. 12 shows a state during a cutting operation of an electromagnet according to a third embodiment of the present invention.

FIG. 13 shows a structure of a vacuum circuit breaker to which the electromagnet of the present invention is applied.

FIG. 14 shows a structure around a contact pressure spring 43 in the vacuum circuit breaker of the present invention.

FIG. 15 shows an example of a coupling method of electromagnets in a vacuum circuit breaker using a plurality of electromagnets of the present invention.

FIG. 16 shows another example of a method of coupling electromagnets in a vacuum circuit breaker using a plurality of electromagnets of the present invention.

[Explanation of symbols]

 Reference Signs List 1 movable iron core 2 fixed iron core 2a, 2e steel pipe 2b convex steel material 2c ring-shaped steel plate 2d, 2f rectangular flat plate 2g cylinder 3 coil 4 projecting part 5 plunger 6 disk-shaped steel plate 6a cylindrical flat plate 7 connecting member 10 electromagnet 15, 15a pipe Reference Signs List 18 rectangular flat plate 20 vacuum circuit breaker 21 thin plate 30 vacuum valve 43 contact pressure spring 45 blocking spring F suction force g gap L gap O magnetic field path W load Φ magnetic field.

Continued on the front page (72) Inventor Yasuaki Suzuki 1-1-1, Kokubuncho, Hitachi City, Ibaraki Prefecture Inside the Electric Systems Division, Hitachi, Ltd. (72) Inventor Masato Yabu 1-1-1 Kokubuncho, Hitachi City, Ibaraki Prefecture Hitachi, Ltd.Electrical Systems Division (72) Inventor Toru Tanimizu 1-1-1, Kokubuncho, Hitachi City, Ibaraki Prefecture Hitachi, Ltd.Electrical Systems Division (72) Inventor Yasuzo Shibata, Kokubuncho, Hitachi City, Ibaraki Prefecture 1-1 1-1, Hitachi, Ltd. Electric Systems Division (72) Inventor Takashi Kadowaki 3-2-2, Samachi, Hitachi, Ibaraki Pref. Hitachi Engineering Services, Ltd. (72) Inventor Tomoyuki Kii Hitachi, Ibaraki 1-1-1 Kokubu-cho F-term in Hitachi Systems, Ltd. Electric Systems Division 5E048 AC05 AD02

Claims (10)

[Claims] 1. An electromagnet comprising a coil, a movable core moving on a central axis of the coil, and a fixed core provided on an upper surface, a lower surface, and an outer peripheral surface of the coil. An electromagnet, wherein the electromagnet is disposed in a gap surrounded by the fixed core, and the movable core is attracted to the fixed core by a magnetic field generated by the permanent magnet. 2. An electromagnet comprising a coil, a movable core moving on a central axis of the coil, and a fixed core provided on an upper surface, a lower surface, and an outer peripheral surface of the coil, wherein the movable core of the fixed core is provided. The movable iron core is provided with a plunger and a steel plate fixed to the end thereof, and an end face of the plunger and the fixed iron core are provided on the side where the magnetic core is inserted.
The steel plate and the protrusion are configured to face each other in the same direction, and the plunger, the protrusion, the steel plate,
An electromagnet, wherein a permanent magnet is provided in a region surrounded by the fixed iron core. 3. The electromagnet according to claim 2, wherein the distance between the end face of the plunger and the fixed iron core is shorter than the distance between the steel plate and the protrusion. 4. A coil, a movable iron core moving on a central axis of the coil, fixed iron cores provided on both axial end surfaces and an outer peripheral surface of the coil, and currents flowing in the forward and reverse directions through the coil. And a power supply capable of moving the movable core toward the fixed core when the coil is energized in the forward direction, wherein the fixed core has one end face in the axial direction of the coil. A fixed core upper member provided so as to cover the fixed core upper member, a permanent magnet is disposed on an upper surface of the fixed core upper member, and the movable core faces an upper surface of the fixed core upper member with the permanent magnet interposed therebetween. An electromagnet comprising: a flat plate member having a surface to be formed; and a plunger member having a cylindrical surface facing the inner peripheral surface of the coil. 5. A current circuit capable of selectively flowing forward and reverse currents through the coil, wherein a magnetic field in the same direction as the magnetic field generated by the permanent magnet when a forward current flows is provided. The suction operation is performed by generating the electric current, and the release operation is performed by canceling out the magnetic field generated by the permanent current when the electric current flows in the reverse direction.
The electromagnet according to any one of the above. 6. A gap g1 between an inner peripheral surface of the fixed core upper member and a cylindrical surface of the plunger member is smaller than an axial thickness t of the permanent magnet.
Electromagnet as described. 7. The electromagnet according to claim 4, wherein a magnetic member is interposed between said plate member side end surface of said plunger member and said plate member. 8. The permanent magnet according to claim 1, wherein the permanent magnet is selected from permanent magnets including rare earth samarium-cobalt magnets, neodymium magnets, alnico magnets, and ferrite magnets. The electromagnet according to any one of claims 1 to 7. 9. An electromagnet according to claim 1, comprising: a contact which is detachable from said electromagnet; and a cut-off spring for opening said contact, wherein said coil of said electromagnet is provided. A power supply circuit capable of selectively flowing forward and reverse currents is provided, and when current flows in the forward direction, the contacts are turned on while accumulating the spring, and turned on by the attractive force of the permanent magnet. Maintaining the state, canceling the magnetic flux created by the permanent current when flowing a current in the opposite direction to the coil,
An operation mechanism for a switch, wherein the operation is interrupted by the force of the interruption spring. 10. The switch operating mechanism according to claim 9, wherein a plurality of the same electromagnets are used in combination.