JP2006222438A - Electromagnet and operating mechanism of switching device using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electromagnet which does not perform inverse excitation of a permanent magnet and in whose magnetic path made by a coil current no permanent magnet exists, and an operating mechanism of a switching device using the same. <P>SOLUTION: The electromagnet is composed by including a moving core 1, coil 3 set up by surrounding the moving core 1, and fixed iron core 2 set up by surrounding the coil 3. The fixed iron core 2 is formed by including a first square shape plate 2f provided at the lower surface side of the coil 3 having a circular aperture at the center and concentric with the coil, a concentric steel pipe 2e which is mounted on the first square shape plate 2f and provided by surrounding the coil 3, and a second square shape plate 2d which is mounted at the upper edge of the steel pipe 2e and having a circular aperture at the center concentric with the coil 3. A permanent magnet 12 is placed and fixed on the upper surface of the second square shape plate 2d. The moving core 1 is formed by including the magnetic substance facing with the permanent magnet 12. The fixed iron core 2 is formed by pinching the steel pipe 2e with a rod 14, which is inserted into holes at four corners of the first and second square shape plates or at two corners on a diagonal line, and nuts screwing with the rod 14. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an electromagnet and a configuration of an operation mechanism of a switchgear using the electromagnet, and more particularly to an electromagnet that suppresses demagnetization of a permanent magnet and a highly reliable switchgear operation mechanism to which the electromagnet is applied.

  The operation mechanism of the switchgear includes an electric spring operation mechanism, a hydraulic type and a pneumatic type operation mechanism. Usually, these operation mechanisms have a relatively high production cost due to a large number of parts and a complicated link mechanism. One of the methods for simplifying the link mechanism is an operation mechanism using an electromagnet. For example, in the vacuum contactor described in Patent Document 1, an electromagnet is used for a closing operation, and an interrupted spring stored simultaneously with the closing is used. Release to open contact. In the operation mechanism described in Patent Document 2, a plunger that penetrates two coils for making and shutting off is provided, and both making and shutting operations are performed by an electromagnet. Further, in Patent Document 3, the closing state is performed by the individually provided movable member driving spring by maintaining the closing state using the attractive force of the permanent magnet and performing reverse excitation with the coil current. In this case, there is an advantage that the coil may be a single coil regardless of whether the coil is turned on or off.

JP-A-5-234475 Japanese National Patent Publication No. 10-505940 JP 2000-249092 A

  However, conventional electromagnets with permanent magnets have the following drawbacks. Permanent magnets include rare earth samarium-cobalt magnets, neodymium magnets, alnico magnets, and ferrite magnets. When a neodymium magnet having a high residual magnetic flux density and a relatively low cost is used, the electromagnet can be made small and inexpensive. However, the neodymium magnet has a large coercive force of 1000 kA / m and a magnetizing magnetic field of 2000 kA / m (corresponding to a magnetic flux density of 2.5 T) or more is required. Therefore, it is practically impossible to magnetize the permanent magnet with the coil of the incorporated electromagnet, and the magnet after magnetizing must be incorporated.

  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, the factor that demagnetizes the permanent magnet must be eliminated as much as possible. In the electromagnet with a permanent magnet described in Patent Document 3, a blocking operation is performed by applying a reverse magnetic field directly to the permanent magnet. By repeatedly applying reverse energy to the permanent magnet, there is a risk of demagnetization, that is, a reduction in life.

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

  In addition, dimensional errors that occur in the manufacturing stage are unavoidable in the thickness of the permanent magnet and the iron core, and due to this dimensional error, the gap at the stroke end between the permanent magnet and the movable iron core that moves forward and backward is changed. . The throwing characteristics, blocking characteristics, and throwing state holding force (adsorption force) are changed by the gap. 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 manufacturing an inexpensive electromagnet.

  The present invention has been devised as a means for solving the above-mentioned problems. The object of the present invention is to provide a long-life and high-performance without direct reverse excitation of the permanent magnet and no permanent magnet in the magnetic path created by the coil current. An object of the present invention is to provide an efficient electromagnet and an operation mechanism of a switchgear using the electromagnet.

  That is, the present invention that solves the above-described problem includes a movable iron core 1, a coil 3 provided so as to surround the movable iron core 1, and a fixed iron core 2 provided so as to surround the coil 3. The iron core 2 is provided on the lower surface side of the coil 3 and is placed on the first rectangular flat plate 2f having a circular opening concentric with the coil at the center, and the coil 3 mounted on the first rectangular flat plate 2f. A concentric steel pipe 2e provided in an enclosed manner, and a second rectangular flat plate 2d placed on the upper end of the steel pipe 2e and having a circular opening concentric with the coil 3 at the center, A permanent magnet 12 is fixedly disposed on the upper surface of the second rectangular flat plate 2d, the movable iron core 1 is formed to include a magnetic body facing the permanent magnet 12, and the fixed iron core 2 is composed of the first and second magnets. Is inserted into the four corner holes of the square plate or the two diagonal corner holes. Rod 14 is an electromagnet which is formed by sandwiching the steel pipe 2e a nut screwed to the rod 14.

  The electromagnet includes a cylinder disposed concentrically with the steel pipe on an upper surface of the second square flat plate, and a third square flat plate stacked on the upper surface of the cylinder, and the rod further includes the third square plate. It may be inserted into holes at the four corners of the rectangular flat plate or at the two diagonal corners, and the cylinder and the third rectangular flat plate may be fixed together.

  Further, a permanent magnet is disposed on the upper surface of the second rectangular flat plate, and the movable iron core includes a cylindrical flat plate having a surface facing the upper surface of the second rectangular flat plate with the permanent magnet interposed therebetween, and the coil. It is good also as an electromagnet comprised by the plunger member provided with the cylindrical surface which opposes an internal peripheral surface, and the thin-plate magnetic member is interposed between the end surface by the side of the said cylindrical flat plate of the said plunger member, and the said cylindrical flat plate.

  The electromagnet includes a power supply circuit capable of selectively passing a current in the forward direction and the reverse direction in the coil 3, and a magnetic field in the same direction as a magnetic field generated by the permanent magnet 12 when a current is passed in the forward direction. Is generated by performing a suction operation, canceling the magnetic field generated by the permanent magnet 12 when a current flows in the opposite direction, and performing a release operation.

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

  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 includes the above-described electromagnet, a contact point that can be separated from and separated from the electromagnet, and a breaking spring that opens the contact point, and selectively allows forward and reverse currents to flow through the coil 3 of the electromagnet. A power supply circuit is provided, and when a current flows in the forward direction, the contact spring is turned on while accumulating the breaking spring, the applied state is maintained by the attractive force of the permanent magnet 12, and the coil 3 is reversed. It is an operating mechanism of the switchgear that cancels out the magnetic flux generated by the permanent magnet 12 when current is passed, and interrupts it with the force of the interrupting spring.

  It is desirable to use a combination of a plurality of electromagnets used in the operation mechanism in accordance with the capacity of the switchgear.

  That is, in the case of the electromagnet configured as described above, the magnetic field generated by passing a current in the reverse direction through the coil does not penetrate the permanent magnet during the cutting operation, so that the permanent magnet is not directly reverse-excited and the coil Since there is no permanent magnet in the magnetic path created by the current, there is no cause for demagnetizing the permanent magnet, and it is possible to use a neodymium-based permanent magnet, which can provide an electromagnet with a long life and excellent efficiency.

  Further, by interposing a magnetic member between the end surface of the plunger member on the cylindrical flat plate side and the cylindrical flat plate, the thickness of the magnetic member is changed, or the magnetic member is made of a thin plate material, By changing the number of plate members, it is possible to easily adjust the gap at the stroke end of the movable core between the permanent magnet and the movable core that moves forward and backward. That is, the characteristics can be stabilized without tightening the tolerances of the parts, and an inexpensive and highly reliable electromagnet can be provided. Furthermore, by applying an operating mechanism of the switchgear to the electromagnet, it is possible to realize a switchgear that is small, inexpensive, and highly reliable.

  According to the electromagnet of the present invention and the operating mechanism of the switchgear using the electromagnet, since the permanent magnet is not reversely excited, a small, inexpensive and highly reliable product can be provided.

  Reference examples and examples of the present invention will be described with reference to FIGS.

(Reference Example 1)
Reference Example 1 of the present invention will be described with reference to FIGS.

  FIG. 1 is a cross-sectional view of an electromagnet 10 that is Reference Example 1 of the present invention. The electromagnet 10 has an axisymmetric structure, and a symbol for structural description is added to the right half of the figure, and the magnetic field B (chain line) generated by the current flowing through the permanent magnet 12 and the coil 3 is shown on the left half.

  The movable iron core 1 is composed of a plunger 5 penetrating on the central axis of the coil 3 and a disk-shaped steel plate 6 fixed to the end thereof, and a load W is applied by a nonmagnetic connecting member 7 fixed to the end of the plunger 5. Connect to. The load W exerts a force to drive the movable iron core 1 upward while the electromagnet 10 is attracted. 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 bodies. 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, or may be fixed by welding. Further, the steel pipe 2a and the convex steel material 2b, or the steel pipe 2a and the ring-shaped steel plate 2c may be manufactured by cutting from a cylindrical material. Here, the steel material 2b has a convex shape, but it may of course be a simple flat plate. However, it is known that if the gap X between the end face of the plunger 5 and the fixed iron core 2 is provided near the center of the coil 3, the leakage magnetic flux is reduced, and it is better to use a convex steel material. Further, 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 insulator or a non-magnetic metal (aluminum, copper, etc.) and a winding 3b.

  The ring-shaped steel plate 2c is screwed into the steel pipe 2a relatively deeply and is provided with a magnetic projection 4. The electromagnet 10 of this reference example has a structure in which the end surface of the plunger 5 and the convex steel material 2b, the disc-shaped steel plate 6 and the protruding portion 4 face each other in the same direction. The distance g between the side surface of the plunger 5 and the ring-shaped steel plate 2c was made shorter than the stroke length of the movable iron core. The reason for this will be described later. Further, the distance X between the end face of the plunger 5 and the convex steel material 2b is made shorter than the distance L between the disc-shaped steel plate 6 and the protruding portion 4, and the plunger 5 and the convex steel material 2b come into contact when the suction operation is completed. It becomes a state.

  The ring-shaped permanent magnet 12 is disposed 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 holding metal fitting for the permanent magnet 12 made of a non-magnetic material such as SUS, for example, and the holding metal fitting 13 is fixed in a manner to be screwed into the steel pipe 2a. The holding metal fitting 13 provides a gap between the permanent magnet 12 and the protruding portion 4, in order to prevent the magnetic flux generated by the permanent magnet 12 from being short-circuited by the protruding portion 4.

  The operation of the electromagnet 10 of this reference example will be described with reference to FIGS. 2 shows a state immediately after the start of the suction operation, FIG. 3 shows a state immediately before the completion of the suction operation, FIG. 4 shows a state after the completion of the suction operation, and FIG. 5 shows a state during the release operation.

  When the coil 3 is energized by an external power supply circuit (not shown), the attractive force F0 acts on the end face of the plunger 5, and the movable iron core 1 starts to move downward. Here, since the distance g between the side surface of the plunger 5 and the ring-shaped steel plate 2c is set to be shorter than the stroke length of the movable iron core 1, the magnetic field Bc generated by the coil current passes through the path O1. Here, it is necessary to set the direction of the coil current and the polarity of the permanent magnet 12 in advance so that the direction of the magnetic field Bm and the direction of the magnetic field Bm generated by the permanent magnet 12 are in the direction of the arrow in FIG. Note that 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. 3 is reached. As the movable iron core 1 moves, the distance L between the disk-shaped steel plate 6 and the protruding portion 4 decreases, and becomes shorter than the distance 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 be diverted to the path O2, and most of it flows through the path O2 when the operation is completed. In other words, along with the movement of the movable iron core 1, in addition to the suction force F0 acting on the end surface of the plunger 5, the suction force F1 also acts between the disk-shaped steel plate 6 and the protruding portion 4. In the state immediately before completion of the attraction operation, the magnetic force B0 of the permanent magnet 12 passes through the path O3, so that the attraction force F0 is further increased.

  When the coil 3 is turned off after the operation of the movable iron core 1 is completed, the attracted state is maintained by the attracting force of the permanent magnet 12. Even after the attraction operation is completed, there is a gap between the disk-shaped steel plate 6 and the protrusion 4, so that the magnetic field Bm generated by the permanent magnet 12 passes through the path O <b> 3. The suction state of the movable core 1 and the fixed core 2 is maintained by the suction force F0.

  The release operation will be described with reference to FIG. The release operation is performed by applying a current in the direction opposite to that in the suction operation to the coil 3. 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 surface of the plunger 5 is reduced, and the movable iron core 1 moves upward by the load force. However, since the attractive force Fr acts simultaneously between the disk-shaped steel plate 6 and the protruding portion 4 due to the magnetic field Bc, there is a possibility that when the excessive current is applied to the coil 3, the suction operation is performed again. It is necessary to provide a means for limiting the coil current by balance with the load force and immediately interrupting the coil current after the release operation is completed.

  Next, the effect of this reference example will be described. In the conventional electromagnet with a permanent magnet, the permanent magnet 12 exists in the magnetic path created by the coil current, and thus the permanent magnet 12 is directly reverse-excited during the releasing operation. If reverse energy is continuously applied to the permanent magnet 12 by repeated operation, there is a risk of demagnetization. In the electromagnet of the present reference example, the permanent magnet 12 is arranged in the gap surrounded by the movable iron core 1 and the fixed iron core 2, that is, arranged in the magnetically shielded region, so that the magnetic field Bc generated by the coil current directly acts on the permanent magnet 12. There is nothing. Even in the releasing operation, no reverse energy is applied to the permanent magnet 12. The risk of demagnetization is avoided, resulting in a long-life and highly reliable electromagnet.

  Further, the permeability of the permanent magnet 12 is almost the same as that of air. If the permanent magnet 12 exists in the magnetic path created by the coil current, the magnetic resistance viewed from the coil increases. At the start of the operation, a gap corresponding to the stroke plus the thickness of the permanent magnet 12 exists, and the ampere turn necessary for the operation increases. In the electromagnet 10 of the present embodiment, since the permanent magnet does not exist in the magnetic path created by the coil current, the magnetic resistance is small and the efficiency is high.

(Reference Example 2)
Reference Example 2 of the present invention will be described with reference to FIGS.

  FIG. 6 is a cross-sectional view of an electromagnet 10 that is Reference Example 2 of the present invention. The movable iron core 1 is composed of a plunger 5 penetrating on the central axis of the coil 3 and a disk-shaped steel plate 6 fixed to the end thereof, and a load is applied by a nonmagnetic connecting member 7 fixed to the 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 bodies. 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, 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 insulator or a non-magnetic metal (aluminum, copper, etc.) and a winding 3b.

  The ring-shaped permanent magnet 12 is fixed on the ring-shaped steel plate 2c. Reference numeral 15 is a tube made of a nonmagnetic member such as SUS, for example, and is fixed to the steel tube 2a with the permanent magnet 12 sandwiched therebetween. Since a large force is not applied to the tube 15, it may be fixed with a screw 16 or the like. The reason why the tube 15 is made of a nonmagnetic member is to prevent the magnetic field of the permanent magnet 12 from being short-circuited by the tube 15. Further, a lid 17 made of a nonmagnetic member is attached to the end of the tube 15, and a rod 8 fixed to the movable iron core 1 passes therethrough. The lid 17, the convex steel material 2b, the connecting member 7 and the rod 8 prevent the axial displacement of the movable iron core 1.

  The distance X between the end surface 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 12 is destroyed. To avoid.

  The operation of the electromagnet 10 of this reference example will be described with reference to FIGS. 6 to 9 show a cross section of the electromagnet 10, and a symbol for explaining the structure is added to the right half, and a 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 longer than the distance g between the permanent magnet 12 and the plunger 5, and the magnetic field Bm produced by the permanent magnet 12 is As shown in FIG. 6, it extends only to the periphery of the permanent magnet 12. 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), the attractive force F0 acts on the end face of the plunger 5 by the magnetic field Bc caused by the coil current, and the movable iron core 1 starts to move downward. Here, since the distance g between the side surface of the plunger 5 and the ring-shaped steel plate 2c is set to be 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 direction of the permanent magnet 12 must be set in advance so that the direction of the magnetic field Bc caused by the coil current and the direction of the magnetic field Bm of the permanent magnet 12 are in the direction of the arrow shown in FIG. Note that 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. 7 is eventually reached. As the movable iron core 1 moves, the distance L between the disk-shaped steel plate 6 and the permanent magnet 12 decreases and becomes shorter than the distance g between the plunger 5 and the ring-shaped steel plate 2c (g> L). The magnetic field Bm of the magnet 12 passes through the path O5. That is, as the movement of the movable iron core 1 proceeds, the attractive force F1 acts between the disk-shaped steel plate 6 and the permanent magnet 12 as well as the attractive force F0 acting on the end face of the plunger 5. Further, since the magnetic field Bm of the permanent magnet 12 passes through the opposing surface of the plunger 5 and the convex steel material 2b, the attractive force F0 is further increased.

  When the coil 3 is excited after the operation of the movable core 1 is completed, the attractive force F0 and the attractive force F1 are acted on 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 in the direction opposite to that in the suction operation to the coil 3. The magnetic field Bc generated by the coil current flows through the path O6 and cancels the magnetic field Bm generated by the permanent magnet 12. The suction force F0 is reduced, and the movable iron core 1 moves upward by the load force.

  The effect of this reference example will be described. Similar to the electromagnet of Reference Example 1, 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. Further, the permeability of the permanent magnet 12 is almost the same as that of air. If the permanent magnet 12 exists in the magnetic path created by the coil current, the magnetic resistance viewed from the coil increases. At the start of operation, a gap corresponding to the stroke plus the thickness of the permanent magnet 12 exists, and the required ampere turn increases. In the electromagnet 10 of the present embodiment, since the permanent magnet does not exist in the magnetic path created by the coil current, the magnetic resistance is small and the efficiency is high.

  Furthermore, the electromagnet of this reference example has the following effects. In the release operation, the electromagnet of the reference example 1 has an attractive force F1 between the disk-shaped steel plate 6 and the magnetic protrusion 4 due to the magnetic field Bm generated by the coil current. There was a possibility of suction operation. Therefore, it is necessary to provide means for limiting the coil current by balance with the load force and immediately interrupting the coil current after the release operation is completed. However, in the electromagnet of this reference example, there is no portion that generates an attractive force by the magnetic field Bc by the coil current, and the attractive operation is not performed again. Therefore, it is not necessary to limit the coil current by balance with the load force and to provide means for interrupting the coil current immediately after the release operation is completed.

Example 1
Embodiment 1 of the present invention will be described with reference to FIG. 9 (on state) and FIG. 10 (off state). 9 and 10 are cross-sectional views of an electromagnet 10 according to an embodiment of the present invention. FIG. 9 shows the electromagnet when the switchgear is turned on when coupled to the switchgear, and FIG. The electromagnet when the switchgear is turned off when coupled is shown. In the following description, the on state and the off state refer to the state of the electromagnet when the electromagnet is coupled to the switchgear and the switchgear is in the on state or the off state.

  The coil 3 includes a bobbin 3a made of an insulator or a nonmagnetic metal (aluminum, copper, etc.) and a winding 3b.

  The illustrated electromagnet 10 is a fixed body made of a coil 3, a movable iron core made of a magnetic material that moves on the central axis of the coil 3, and a magnetic material provided so as to cover both axial end faces and the outer peripheral surface of the coil 3. An iron core and a power source (not shown) capable of flowing a current in the forward direction and the reverse direction through the coil 3 are configured. When the coil 3 is energized in the forward direction, the movable iron core is moved in a direction toward the fixed iron core, that is, from right to left in the figure. In the following description, for the sake of convenience, the direction is shown with the right side as the upper side and the left side as the lower side in FIG.

  The fixed iron core is provided so as to cover one end surface of the coil 3 in the axial direction, and a second rectangular flat plate 2d which is a fixed iron upper member having a circular opening concentric with the coil 3 in the center portion; A first rectangular flat plate 2f which is a fixed core lower member provided so as to cover the other end surface in the axial direction of the coil and which has a circular opening concentric with the coil 3 in the center, and the second rectangular flat plate 2d A steel pipe 2e sandwiched between the first rectangular flat plate 2f and covering the outer peripheral surface of the coil 3, and a cylinder 2g disposed concentrically with the steel pipe 2e on the upper surface of the first rectangular flat plate 2f. It is configured to include. The second rectangular flat plate 2d, the first rectangular flat plate 2f, the steel pipe 2e, and the cylinder 2g are all magnetic bodies, and the first rectangular flat plate 2f and the cylinder 2g are fixed with screws or the like or are integrally welded. ing. 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 second rectangular flat plate 2d, and is fixed by an adhesive. The permanent magnet 12 may be any material of neodymium, samarium, alnico, neodymium bond, and ferrite. In addition, the illustrated permanent magnet 12 is a single annular magnet, but it is not always necessary to have a continuous annular shape. You may arrange | position on the upper surface of the square flat plate 2d. However, also in this case, it is necessary that the area of the surface facing the cylindrical flat plate 6a described later is an area that can exhibit the required adsorption force.

  The movable iron core is fitted into the rod 19 and a nonmagnetic rod 19 inserted through the centers of the opening of the second rectangular flat plate 2d, the opening of the first rectangular flat plate 2f, the steel pipe 2e, and the cylinder 2g. A plunger 5 that is a columnar magnetic body that is fixed in this manner, and a cylindrical plate 6 a that is a magnetic body that is disposed above the plunger 5 via a thin plate 21 that is a magnetic member and is fixed to the rod 19; It is comprised including. The lower surface of the cylindrical flat plate 6 a faces the upper surface of the rectangular flat plate 2 d across the permanent magnet 12, and the outer peripheral surface of the plunger 5 faces the inner peripheral surface of the coil 3. In other words, 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 moves inside thereof in the axial direction. Although the outer diameter of the cylindrical flat plate 6 a is larger than the diameter of the central opening of the permanent magnet 12, 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 second rectangular flat plate 2d are concentric and have the same diameter, and the axial thickness t of the permanent magnet 12 is the center of the second rectangular flat plate 2d. The distance between the inner peripheral surface of the opening and the outer peripheral surface of the plunger 5 is larger than the distance g1.

  The outer diameter of the cylinder 2g is smaller than the inner diameter of the coil 3, and is the same as the outer diameter of the plunger 5. Further, the inner diameter of the cylinder 2g is set such that the rod 19 can pass freely. That is, the lower surface of the plunger 5 faces the upper surface of the cylinder 2g, and when the movable iron core moves to the left in the axial direction, the limit of movement is determined by the point where the lower surface of the plunger 5 and the upper surface of the cylinder 2g come into contact.

  On the upper side of the permanent magnet 12, a tube 15 a made of a non-magnetic material (stainless steel is used in this embodiment) is arranged concentrically with the coil 3, and the tube 15 a is sandwiched between the permanent magnet 12 and the permanent magnet 12. A third rectangular flat plate 18 is arranged. The third rectangular flat plate 18 may be magnetic or non-magnetic. Holes are passed through the four corners of the first square flat plate 2f, the second square flat plate 2d, and the third square flat plate 18 or two diagonal corners so that the rods 14, which are non-magnetic materials with threads at both ends, pass through. And the whole is fixed by tightening both ends of the rod 14 with nuts.

  A hole through which the rod 19 passes concentrically with the coil 3 is formed in the third rectangular flat plate 18 and the first rectangular flat plate 2f, and a bearing or a dry bearing is provided in the hole portion, and the rod 19 slides. The friction at the time is reduced and maintenance is reduced.

  The on state of FIG. 9 is held by the attractive force of the permanent magnet 12 (generated by the magnetic flux φ1). That is, the engaged state is the attractive 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. Is done. The lower surface of the plunger 5 may not be in direct contact with the upper surface of the cylinder 2g, but a thin nonmagnetic material may be sandwiched therebetween.

  When the electromagnet is assembled, a plurality of thin plates 21 having the same thickness are prepared, and the number of the thin plates 21 sandwiched between the plunger 5 and the cylindrical flat plate 6a is changed, so that the permanent magnet 12 and the cylindrical flat plate 6a in the state shown in FIG. A gap g2 having a desired size is formed between the two. The reason for creating the gap g2 is that when the cylindrical flat plate 6a directly collides with the permanent magnet 12 during the on-operation, 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 so that the gap g2 in the on state is as close to 0 as possible, the magnetic resistance can be reduced and the attractive force can be increased. As a result, even if the volume of the permanent magnet 12 is reduced by reducing the thickness of the permanent magnet or reducing the surface area attracted to the second rectangular flat plate 2d, the conventional attractive force can be secured. Therefore, the cost of the permanent magnet that greatly depends on the volume is reduced, and a small and inexpensive electromagnet can be obtained. Further, by changing the number of the thin plates 21, the value of the gap g2 in the on state can be brought close to a desired constant value, so that the attraction force and the on / off operation characteristics of the permanent magnet in the on state can be stabilized. And the reliability of the electromagnet can be improved.

  Instead of using multiple thin plates of the same thickness to adjust the value of the gap, prepare plates of various thicknesses with different thicknesses, one of which has an appropriate thickness Alternatively, the gap value may be adjusted by combining different thicknesses.

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

  During the turning-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). The 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 side in the drawing, that is, a force for attracting the movable iron core to the fixed iron 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 a force generated by the magnetic flux obtained by combining the magnetic flux φ2 and the magnetic flux φ1.

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

  At this time, since the thickness t of the permanent magnet 12 is larger than the gap g1 between the inner peripheral surface of the opening of the center of the second rectangular flat plate 2d and the outer peripheral surface of the plunger 5, it is formed by a reverse current. The magnetic flux φ5 does not pass through the permanent magnet 12 as shown in FIG. This is because the magnetic permeability φ5 due to the reverse current has a small magnetic resistance and the magnetic path shown in FIG. If the permanent magnet is continuously subjected to reverse excitation, it may be demagnetized. However, in the electromagnet of this embodiment, the permanent magnet is not subjected to reverse excitation. A highly reliable electromagnet can be obtained.

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

  In this embodiment, the electromagnet 10 described in Reference Examples 1 and 2 and Embodiment 1 is applied to the operation mechanism of the switchgear. FIG. 13 is a side sectional view of a three-phase vacuum circuit breaker 20 to which the electromagnet 10 described in Reference Example 2 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 other switchgear such as a gas circuit breaker. Moreover, although the example which applied the electromagnet 10 of the reference example 2 is described, the electromagnet of the reference example 1 or Example 1 is applicable similarly.

  The vacuum circuit breaker 20 includes a vacuum valve 30, an operation mechanism unit 40, an insulating mount 31, and an operation space 50 that houses the control circuit 51 and the electromagnet 10. The vacuum valves 30 are installed in a state where three phases are arranged in the depth direction of the drawing. The three vacuum valves 30 are connected by a shaft 41 in the operation mechanism unit 40 and are driven by a single electromagnet 10.

  The vacuum valve 30 is kept in a vacuum state by a vacuum container composed of upper and lower end plates 32 and an insulating cylinder 33. A fixed contact 37 and a movable contact 38 are disposed in the vacuum valve 30 and are turned on and off by 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 fixed contact 37 and the movable contact 38 can be brought into and out of contact with each other while the vacuum state is maintained by the bellows 34.

  Both the vacuum valve 30 and the electromagnet 10 are connected to the shaft 41, and the driving force generated by the electromagnet 10 is applied to the movable conductor 36. The movable conductor 36 is electrically insulated from the operating mechanism by an insulating rod 63 and is connected to a lever 42 fixed to the shaft 41. The movable iron core 1 of the electromagnet 10 is coupled to the lever 44 by the connecting member 9.

  In the closing operation, the contact pressure spring 43 and the blocking spring 45 must be stored simultaneously. The contact pressure spring 43 is a spring for applying contact pressure to the contact at the time of closing, and the cutoff spring 45 is a spring for performing a cutoff operation.

  The contact pressure spring 43 is accommodated in the insulating rod 63. The structure around the contact pressure spring 43 is shown in FIG. The contact pressure spring 43 is accommodated in a contact pressure spring holder 43 a 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 a pin 43c. The connecting member 43b is provided with a hole slightly larger than the outer diameter of the pin 43c, and the contact pressure spring holder 43a is provided with 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 to move in the elliptical hole 43d (downward in the figure), 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 the top plate 46 of the operation mechanism unit 40 and the plate 47 fixed to the connecting member 9. The shut-off spring 45 is always compressed during the closing operation.

  The operation of the switchgear will be described. When the coil 3 is energized and the magnetic field Bc shown in FIG. 7 is generated, the movable iron core 1 is driven downward by the attractive force F0, and accordingly, the movable conductor 36 is moved upward and the contact is turned on. Even if the current of the coil 3 is interrupted after the closing operation is completed, this state is maintained by the attractive force of the permanent magnet 12. In the interruption operation, when a current in the opposite direction to that in the closing operation is applied to the coil 3, the magnetic force B0 of the permanent magnet 12 is canceled and the attractive force F0 is reduced as shown in FIG. The movable conductor 36 is driven downward.

  Next, the effect of the present embodiment will be described. By applying any of the electromagnets 10 of the reference examples 1 and 2 and the embodiment 1 to the switchgear, the permanent magnet 12 used for holding the charged state is not demagnetized, and the long-term guarantee of 20 years is 10,000 times or more. It will be possible to satisfy the multiple operations. That is, it is possible to provide a highly reliable switchgear with a long life.

  In the second embodiment, an example in which one electromagnet is used to drive the switchgear is shown. However, a large load is required for a circuit breaker having a large capacity, that is, requiring a large force for the switching operation. A plurality of electromagnets are used so that a force corresponding to the height can be produced. In this case, an electromagnet having a reference size may be set, and a plurality of reference electromagnets may be combined so that a required opening / closing operation force can be generated.

  FIG. 15 and FIG. 16 show examples of circuit breakers using four electromagnets. 15 and 16 correspond to plan views in a state in which the top plate 46, the insulating base 31, the control circuit 51, the fixed feeder 39, the movable feeder 62 and the like of the operation mechanism unit 40 in FIG. 13 are removed. The method of attaching the electromagnet to the shaft 41 is shown.

  In the example shown in FIG. 15, vacuum valves 30a, 30b, and 30c corresponding to respective phases of the three-phase electric circuit are coupled to the shaft 41 by levers 42a, 42b, and 42c, respectively. 10c and 10d are coupled to the shaft 41 by levers 44a, 44b, 44c and 44d, respectively. That is, each of the four electromagnets individually applies a driving force to the shaft 41.

  In the example shown in FIG. 16, the method of coupling the vacuum valves 30a, 30b, 30c to the shaft 41 is the same as the example shown in FIG. 15, but the method of coupling the electromagnet to the shaft 41 is the same as the example shown in FIG. Different. In FIG. 16, levers 44a and 44b are coupled to both ends of the shaft 41, and a connecting rod 52 for connecting the levers 44a and 44b is pivotally attached to each end of the levers 44a and 44b. The electromagnets 10a, 10b, 10c, and 10d of the same type and the same specification are coupled to the connecting rod 52, and drive force is applied to the shaft 41 via the connecting rod 52 and levers 44a and 44b.

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

Sectional drawing of the electromagnet which is the reference example 1 of this invention is shown. The state immediately after the attraction | suction operation | movement start of the electromagnet which is the reference example 1 of this invention is shown. The state just before completion of attraction | suction operation | movement of the electromagnet which is the reference example 1 of this invention is shown. The state of the attraction | suction operation completion of the electromagnet which is the reference example 1 of this invention is shown. The state in the release operation of the electromagnet which is the reference example 1 of this invention is shown. The state immediately after the attraction | suction operation | movement start of the electromagnet which is the reference example 2 of this invention is shown. The state just before completion of attraction | suction operation | movement of the electromagnet which is the reference example 2 of this invention is shown. The state in the releasing operation of the electromagnet which is the reference example 2 of this invention is shown. The insertion state of the electromagnet which is Example 1 of this invention is shown. The cut state of the electromagnet which is Example 1 of this invention is shown. The state in the turning-on operation of the electromagnet which is Example 1 of this invention is shown. The state in the cutting | disconnection operation | movement of the electromagnet which is Example 1 of this invention is shown. The structure of the vacuum circuit breaker to which the electromagnet of the present invention is applied is shown. The structure of the contact pressure spring 43 periphery part in the vacuum circuit breaker of this invention is represented. The example of the coupling | bonding system of the electromagnet of the vacuum circuit breaker using two or more electromagnets of this invention is shown. The other example of the coupling | bonding method of the electromagnet of the vacuum circuit breaker using two or more electromagnets of this invention is shown.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Movable iron core 2 Fixed iron core 2a, 2e Steel pipe 2b Convex steel material 2c Ring-shaped steel plate 2d 2nd square flat plate 2f 1st square flat plate 2g Cylinder 3 Coil 4 Protruding part 5 Plunger 6 Disc shaped steel plate 6a Cylindrical flat plate 7 Connection Member 10 Electromagnet 15, 15a Tube 18 Third square flat plate 20 Vacuum circuit breaker 21 Thin plate 30 Vacuum valve 43 Contact spring 45 Cut off spring F Attraction force g Distance L Distance O Magnetic path W Load Φ Magnetic field

Claims (4)

  A movable iron core; a coil provided to surround the movable iron core; and a fixed iron core provided to surround the coil. The fixed iron core is provided on a lower surface side of the coil and is provided at a central portion. A first rectangular flat plate having a circular opening concentric with the coil; a concentric steel pipe placed on the first square flat plate surrounding the coil; and placed on an upper end of the steel pipe A second rectangular flat plate having a circular opening concentric with the coil at a central portion thereof, a permanent magnet is fixedly disposed on an upper surface of the second rectangular flat plate, and the movable iron core is attached to the permanent magnet; The steel core is formed by including rods inserted into holes at four corners or two diagonal corners of the first and second rectangular flat plates and nuts screwed to the rods. An electromagnet that is formed by sandwiching it.   2. The electromagnet according to claim 1, further comprising a cylinder disposed concentrically with the steel pipe on an upper surface of the second rectangular flat plate, and a third rectangular flat plate stacked on the upper surface of the cylinder, and the rod further includes: An electromagnet, which is inserted through holes at four corners or two diagonal corners of the third rectangular flat plate, and fixes the cylinder and the third rectangular flat plate together.   3. An electromagnet according to claim 1 or 2, a contact point that can be contacted and separated, and a breaking spring for opening the contact point, wherein currents in a forward direction and a reverse direction are selectively applied to the coil of the electromagnet. A power supply circuit that can flow is provided, and when a current flows in the forward direction, the contact spring is charged while accumulating the breaking spring, and the charged state is maintained by the attractive force of the permanent magnet. An operating mechanism for a switch, wherein when a current is applied, the magnetic flux generated by the permanent magnet is canceled and the magnetic force is interrupted by the force of the interrupting spring. The switch operating mechanism according to claim 3 , wherein a plurality of the same electromagnets are used in combination.

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