JP4483416B2 - Electromagnetic actuator, switch and switch using the same - Google Patents

Description

  The present invention belongs to the technical field of switchgear and relates to an electromagnetic actuator for driving a contact of a switch such as a circuit breaker or a disconnecting switch.

  An electromagnetic actuator is known as a drive mechanism for a contact of a switch (breaker, disconnector) used in a switchgear. In a vacuum circuit breaker having a relatively low rated voltage (mainly 24 kV or less), the contact stroke is short (for example, 10 mm or less), and many electromagnetic actuators are employed. In such a conventional electromagnetic actuator, a rectangular movable core disposed in a reciprocating manner in an inner space of a fixed core made of a magnetic material, a drive coil for driving the movable core, and the movable core And a permanent magnet that is held by the magnetic poles at either the upper end or the lower end of the fixed core (see, for example, Patent Document 1).

US Pat. No. 6,0096,515 (FIGS. 1 and 2)

The driving force F of a general electromagnetic actuator represented by the electromagnetic actuator shown in Patent Document 1 is
F = μ × A × (N × I) ² / (2s ² ) (Formula 1)
It is expressed. Here, N is the number of turns of the drive coil, I is the exciting current energized to the drive coil, μ is the vacuum permeability, and A is the cross-sectional area of the magnetic pole. From Formula 1, it can be seen that as the gap distance s (equal to the stroke of the electromagnetic actuator) between the movable iron core and the end magnetic poles of the fixed core becomes longer, the driving force F decreases in inverse proportion to the square of the gap distance s. By the way, most contactors in the world such as a gas circuit breaker, an air circuit breaker, and a high voltage vacuum circuit breaker (for example, 30,000 V or more) do not have a short contact stroke of 20 mm or more. When a conventional electromagnetic actuator is applied to such a switch with a long contact stroke, the driving force F is reduced.

  In order to ensure the same driving force F even when the contact stroke becomes long, it is necessary to increase the magnetomotive force (N × I). Here, increasing the number of turns N increases the coil resistance, so the voltage must be increased. On the other hand, even if the current I is increased, the capacity (wattage) of the power source must be increased after all. In any case, there is a problem that the power supply is increased in size and cost.

  The present invention has been made to solve the above-described problems, and an electromagnetic actuator that can ensure a sufficient driving force without requiring an increase in the size of a power supply even in a long-stroke switch. provide.

Electromagnetic actuator in the present invention, Ri Do a magnetic material, a fixed core magnetic pole is provided at an end portion, the adjacent first position and the magnetic pole of remote from Oite the magnetic pole to an inner space of the stationary core A movable core disposed in a reciprocable manner between the first position and the second position, and the first position and the second position for driving the movable core from the first position to the second position. An electromagnetic actuator comprising a drive coil disposed between the position and a permanent magnet for holding the movable iron core at the second position when the movable iron core is not driven. An auxiliary magnetic pole is provided between the drive coil and the magnetic pole on the side opposite to the movable iron core at the first position, and at least one auxiliary magnetic pole is further added to the movable iron core in addition to the auxiliary magnetic pole. An auxiliary drive coil is arranged between adjacent auxiliary magnetic poles along the drive direction, and the energization timing of the drive coil and the auxiliary drive coil is set to a position and a direction during driving of the movable core. It is controlled based on this .

  According to this invention, even in a long stroke switch, it is possible to provide an electromagnetic actuator that can ensure a sufficient driving force without requiring a large power source.

Embodiment 1 FIG.
FIG. 1 is a partial cross-sectional perspective view of an electromagnetic actuator for explaining Embodiment 1 of the present invention, and FIG. 2 is a cross-sectional view in the direction of arrow AA. The electromagnetic actuator 100 has a movable iron core 2 that is arranged in a reciprocating manner in an inner space of a fixed core 1 made of a magnetic material. Two drive coils 3 and 4 are arranged above and below the center of the inner space of the fixed core 1 so as to surround the inner space. The movable iron core 2 is driven in the vertical direction in the figure by appropriately controlling energization to the drive coils 3 and 4. Two central magnetic poles 10 are provided so as to oppose each other with the central portion of the inner space of the fixed core 1 sandwiched in the horizontal direction in the figure (the vertical direction of the driving direction of the movable iron core 2). Two yokes 6 are arranged adjacent to the two central magnetic poles 10 so as to face each other with the central magnetic pole 10 interposed therebetween, and permanent magnets 5 are provided on the side of each yoke 6 facing the movable core 2. ing. When the movable core 2 is not driven, the movable core 2 is held by the upper magnetic pole 11 provided at the upper end of the fixed core 1 or the lower magnetic pole 12 provided at the lower end of the fixed core 1. Taking FIG. 1 as an example, the movable iron core 2 is attracted to the upper magnetic pole 11 by forming a magnetic circuit (indicated by a dotted line in FIG. 1) with the permanent magnet 5, the movable iron core 2, the fixed core 1, and the yoke 6. Is retained. An upper auxiliary magnetic pole 111 is provided between the drive coil 3 and the upper magnetic pole 11, and a lower auxiliary magnetic pole 112 is provided between the drive coil 4 and the lower magnetic pole 12.

  Next, the operation will be described. 3 to 5 are partial cross-sectional enlarged views of the electromagnetic actuator 100, and show a state in which the movable iron core 2 moves downward in the figure when the drive coil 4 is energized. First, in FIG. 3, when the drive coil 4 is energized, a magnetic flux is generated around the drive coil 4. Here, the gap distance s between the movable iron core 2 and the magnetic pole 12, the height of the auxiliary magnetic pole 112 is h, the distance d between the stroke line of the movable iron core 2 and the auxiliary magnetic pole 112, and the gap distance between the movable iron core 2 and the auxiliary magnetic pole 112. g. It is assumed that the gap distance g changes as the movable iron core 2 is driven.

  If the stroke of the electromagnetic actuator 100 is increased, the gap distance s is also increased accordingly. In this case, the driving force by the magnetic flux ΦB passing through the path of the gap distance s is as shown in Equation 1, and the driving force decreases as the gap distance s increases.

By the way, by arranging the auxiliary magnetic pole 112, the magnetic flux ΦA passing through the path of the gap distance g is also generated. The driving force by the magnetic flux ΦA in FIG. 3 is obtained by using a component force ratio cos θ = (s−h) / g in the downward direction in the figure.
F = μ × A × (N × I) ² / (2 g ² ) × cos θ (Formula 2)
It is expressed.

In FIG. 3, since the gap distance g is sufficiently shorter than the gap distance s, most of the magnetic flux is the magnetic flux ΦA. That is, the driving force of the electromagnetic actuator 100 is substantially expressed by Equation 2. By arranging the auxiliary magnetic pole 112 so that the driving force F in Equation 2 is sufficiently larger than the driving force F in Equation 1, a sufficient initial driving force can be obtained even with a long stroke. Specifically, the auxiliary magnetic pole 112 may be formed so as to satisfy g ³ <s ³ −s ² h from Equations 1 and 2.

  When the movable iron core 2 moves downward in the figure by the magnetic flux ΦA, both the magnetic flux ΦA and the magnetic flux ΦB are formed as shown in FIG. In this state, the driving force due to the magnetic flux ΦA does not contribute due to the component force ratio cos θ = 0, but the movable iron core 2 moves further downward due to the driving force due to the magnetic flux ΦB and the kinetic energy of the movable iron core 2.

  When the gap distance s becomes sufficiently shorter than the gap distance g due to the movement of the movable iron core 2, most of the magnetic flux becomes the magnetic flux ΦB. Finally, the movable iron core 2 reaches the magnetic pole 12 as shown in FIG. In this state, even if energization of the drive coil 4 is stopped, the magnetic flux generated by the permanent magnet 5 passes through the magnetic pole 12 in the same manner as the magnetic flux ΦB. That is, the path of the gap distance g is not taken. Therefore, the suction holding force when the movable iron core 2 is sucked and held by the magnetic pole 12 is not affected. Similarly, the movable iron core 2 can be moved upward.

  As described above, according to the configuration of the electromagnetic actuator 100 in this embodiment, even when the stroke is long, the auxiliary magnetic poles 111 and 112 can ensure a short effective gap distance from the movable iron core 2 and decrease the initial driving force. Can be prevented. Therefore, the movable iron core 2 can be driven sufficiently without requiring an increase in the size of the power source, and the suction holding force in the drive stopped state is not affected.

  In addition, it is preferable that the fixed core 1 and the movable iron core 2 have a laminated structure. The magnetic material forming the fixed core 1 and the iron forming the movable iron core 2 are usually plated. By forming the fixed core 1 and the movable core 2 in a laminated structure, generation of eddy currents in the movable core 2 can be suppressed. Therefore, the magnetic flux shielding to the movable iron core 2 is eliminated, and the drive controllability is improved.

  Further, as shown in FIG. 6, the auxiliary magnetic pole 112 may be disposed at a position away from the inner space of the fixed core 1. However, the upper end portion of the auxiliary magnetic pole 112 is located between the drive coil 4 and the magnetic pole 12 at the projection position on the inner space. The positional relationship among the auxiliary magnetic pole 111, the drive coil 3, and the magnetic pole 11 not shown is the same.

  Furthermore, in the present invention, the structure of the electromagnetic actuator 100 can be freely modified within the spirit of the invention. For example, the same effect can be obtained even if the fixed core, the movable iron core, the drive coil, and the like are cylindrical and annular. Moreover, as shown in FIG. 7, there is an example in which one drive coil is used and the spring 8 is used as a drive force source in the opposite direction.

Embodiment 2. FIG.
FIG. 8 is a cross-sectional view of the electromagnetic actuator for explaining the second embodiment. In this embodiment, a space is provided between the auxiliary magnetic pole and the upper or lower magnetic pole in the first embodiment, and a drive coil is also arranged in this space. In the figure, a drive coil 3a is provided between the central magnetic pole 10 and the upper auxiliary magnetic pole 111, and a drive coil 3b is provided between the upper auxiliary magnetic pole 111 and the upper auxiliary magnetic pole 11, and the central magnetic pole 10 and the lower auxiliary magnetic pole 112 are provided. A drive coil 4 a is disposed between the lower auxiliary magnetic pole 112 and the lower magnetic pole 12.

  Next, the operation will be described. First, when the drive coil 4a is energized, the movable iron core 2 is driven downward by the magnetic flux generated around the drive coil 4a. At this time, the driving force is expressed by Equation 2, and a sufficient initial driving force can be obtained by the auxiliary magnetic pole 112. Subsequently, when the lower end of the movable iron core 2 is aligned with the upper end of the auxiliary magnetic pole 112, the drive coil 4b is energized. This is because the magnetic flux generated around the drive coil 4a requires a new magnetic flux generated around the drive coil 4b when the driving force contributing downward is not obtained. A downward driving force is continuously applied to the movable iron core 2 by the combined magnetic flux generated by the driving coil 4a and the driving coil 4b. In this way, the movable iron core 2 can reach the magnetic pole 12.

  In addition, after energizing the drive coil 4b, when the lower end of the movable core 2 is aligned with the lower end of the auxiliary magnetic pole 112, the energization to the drive coil 4a may be stopped. For example, if the power sources of the drive coils 4a and 4b are independent, after the movable iron core 2 approaches the magnetic pole 12, the combined magnetic flux by the drive coil 4a and the drive coil 4b and the magnetic flux by only the drive coil 4b This is because there is no difference in the obtained driving force. Further, when the drive coils 4a and 4b are connected in parallel from a single power source, the amount of energization to the drive coil 4b is increased by the amount of energization to the drive coil 4a, so that the drive coil 4a and the drive coil 4b This is because the obtained driving force is larger in the magnetic flux generated by only the driving coil 4b than in the combined magnetic flux.

  Further, when the movable iron core 2 passes by the side of the auxiliary magnetic pole 112, the current from the power source may be switched from the drive coil 4a to the drive coil 4b without generating a combined magnetic flux of the drive coil 4a and the drive coil 4b. In this case, control of the current to the drive coil is facilitated. Here, although the thickness of the auxiliary magnetic pole 112 can be designed as appropriate, from the viewpoint of quickly raising the downward driving force by the magnetic flux of the driving coil 4b when the movable iron core 2 passes by the auxiliary magnetic pole 112, The auxiliary magnetic pole 112 is preferably thin.

Embodiment 3 FIG.
FIG. 9 is a cross-sectional view of an electromagnetic actuator for explaining the third embodiment. In this embodiment, a plurality of auxiliary magnetic poles are arranged along the driving direction of the movable iron core in the first embodiment, and auxiliary driving coils are arranged between adjacent auxiliary magnetic poles. In the figure, four auxiliary magnetic poles 111 are arranged between the central magnetic pole 10 and the upper magnetic pole 11, and four auxiliary magnetic poles 112 are arranged between the central magnetic pole 10 and the lower magnetic pole 12. The drive coil 3 is disposed between the central magnetic pole 10 and the auxiliary magnetic pole 111 adjacent to the upper side thereof. In addition, auxiliary drive coils 31, 32, 33 are arranged between the adjacent auxiliary magnetic poles 111. Similarly, the drive coil 4 is arranged between the central magnetic pole 10 and the adjacent auxiliary magnetic pole 112 below it. In addition, auxiliary drive coils 41, 42, and 43 are disposed between adjacent auxiliary magnetic poles 112.

  The energization timing to the drive coils 3 and 4 and the auxiliary drive coils 31 to 33 and 41 to 43 is controlled based on the position and direction of the movable iron core 2 during driving. FIG. 10 is a time chart for energizing the drive coil 4 and the auxiliary drive coils 41 to 43 when the movable iron core 2 is driven downward.

  First, when the drive coil 4 is energized, the movable iron core 2 is driven downward by the magnetic flux generated around the drive coil 4, and a sufficient initial driving force is obtained by the auxiliary magnetic pole 112. Subsequently, the auxiliary drive coils 41, 42, 43 are sequentially energized. The energization timing to the auxiliary drive coils 41 to 43 is preferably when the lower end of the movable iron core 2 is aligned with the upper end of the auxiliary magnetic pole 112 immediately above the auxiliary drive coils 41 to 43. A downward driving force is continuously applied to the movable iron core 2 by a combined magnetic flux generated by the drive coil 4 and the auxiliary drive coils 41 to 43 sequentially energized. In this way, the movable iron core 2 can reach the magnetic pole 12.

  Further, the energization timings for the drive coils 3 and 4 and the auxiliary drive coils 31 to 33 and 41 to 43 may be modified as shown in FIG. Here, when the lower end of the movable iron core 2 is aligned with the lower end of the auxiliary magnetic pole 112 immediately below the drive coil 4 or the auxiliary drive coils 41 to 42, the energization to the drive coil 4 or the auxiliary drive coils 41 to 42 is stopped. . This suppresses power consumption and does not impair driving efficiency with respect to input power.

  Further, when the movable iron core 2 passes by the side of the auxiliary magnetic pole 112, current from the power source is supplied to the driving coil 4 and the auxiliary driving coils 41 to 43 without generating a composite magnetic flux of the driving coil 4 and the auxiliary driving coils 41 to 43. May be switched sequentially. In this case, control of the current to the drive coil 4 and the auxiliary drive coils 41 to 43 is facilitated.

  In this embodiment, any stroke length can be easily handled by dividing the auxiliary magnetic poles 111 and 112 and the auxiliary driving coils 31 to 33 and 41 to 43 without impairing the driving efficiency of the electromagnetic actuator 100. Furthermore, unevenness may be provided on the surface of the movable iron core 2 to provide a function as an auxiliary magnetic pole.

Embodiment 4 FIG.
FIG. 12 is a configuration diagram of an opening / closing device for explaining the fourth embodiment. This embodiment is an example in which the electromagnetic actuator described in the first embodiment is applied to a switchgear. Needless to say, the electromagnetic actuators of the second to third embodiments can be appropriately changed.

  In the figure, the switch 400 includes a disconnector 200 as a switch, a vacuum circuit breaker 300 as a switch, and a casing 401 that houses the disconnector 200 and the circuit breaker 300. The casing 401 is provided with an operation button 402 for each switch and a monitor 403 such as an ammeter or a voltmeter. The disconnector 200 has a movable contact 202 and two fixed contacts 201, and the electromagnetic actuator 100 is used as a drive mechanism for the movable contact 202. The vacuum circuit breaker 300 has a movable contact 302 and a fixed contact 301, and the electromagnetic actuator 100 is used as a drive mechanism for the movable contact 302.

  In this embodiment, by using an electromagnetic actuator as a drive mechanism for the movable contact of the switch, the number of parts is reduced by half compared to a conventional spring mechanism. As the number of parts is reduced, the probability of failure is reduced and reliability is improved.

  The present invention is particularly suitable for a long stroke electromagnetic actuator, but can also be used to improve the driving efficiency of a conventional short stroke electromagnetic actuator.

FIG. 3 is a partial cross-sectional perspective view of an electromagnetic actuator for explaining the first embodiment. FIG. 3 is a cross-sectional view of an electromagnetic actuator for explaining the first embodiment. FIG. 3 is an enlarged partial cross-sectional view of the electromagnetic actuator for explaining the first embodiment. FIG. 3 is an enlarged partial cross-sectional view of the electromagnetic actuator for explaining the first embodiment. FIG. 3 is an enlarged partial cross-sectional view of the electromagnetic actuator for explaining the first embodiment. FIG. 6 is a partial cross-sectional perspective view showing a modification of the electromagnetic actuator for explaining the first embodiment. FIG. 6 is a partial cross-sectional view showing a modification of the electromagnetic actuator for explaining the first embodiment. FIG. 6 is a cross-sectional view of an electromagnetic actuator for explaining a second embodiment. FIG. 10 is a cross-sectional view of an electromagnetic actuator for explaining a third embodiment. 10 is an energization time chart of an electromagnetic actuator for explaining a third embodiment. 10 is a modification of the energization time chart of the electromagnetic actuator for explaining the third embodiment. FIG. 10 is a configuration diagram of an opening / closing device for explaining a fourth embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Fixed core, 10 Central magnetic pole, 11-12 magnetic pole, 111-112 Auxiliary magnetic pole, 2 Moving iron core, 3-4 Drive coil, 31-33, 41-43 Auxiliary drive coil, 5 Permanent magnet, 100 Electromagnetic actuator, 200 Disconnect , 300 vacuum circuit breaker, 400 switchgear.

Claims (4)

Ri Do a magnetic material, a fixed core magnetic pole is provided at an end portion,
A movable iron core arranged in reciprocatable state and a second position adjacent to said pole and first position away from Oite the magnetic pole to an inner space of the fixed core,
A drive coil disposed between the first position and the second position for driving the movable iron core from the first position to the second position ;
In an electromagnetic actuator comprising a permanent magnet for holding the movable iron core in the second position when the movable iron core is not driven,
An auxiliary magnetic pole between said drive coil opposite said pole provided with said movable iron core is in said first position around the said drive coil,
In addition to the auxiliary magnetic pole, at least one auxiliary magnetic pole is arranged along the driving direction of the movable iron core, and an auxiliary driving coil is arranged between adjacent auxiliary magnetic poles, and the driving coil and the auxiliary driving are arranged. energization timing to the coil, wherein the to that conductive magnetic actuator that is controlled based on the position and direction of drive of the movable core. The electromagnetic actuator according to claim 1 , wherein the movable iron core and the fixed core have a laminated structure. A switch having a movable contact and a fixed contact, wherein the electromagnetic actuator according to claim 1 or 2 is used as a drive mechanism for the movable contact. 3. A switchgear comprising a switch having a movable contact and a fixed contact, and a housing for housing the switch, wherein the switch uses the electromagnetic actuator according to claim 1 or 2 as a drive mechanism for the movable contact. A switchgear characterized by

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