JP2007018954A - Ac power relay - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To achieve an AC power relay with a simple configuration that is hardly affected by reduction in power supply voltages such as instantaneous voltage drop. <P>SOLUTION: In the AC power relay 10 which is provided with an electromagnet 14 where an electromagnetic coil 16 is wound around an iron core 20, with an armature 24 which is attracted to the electromagnet 14 when an AC voltage is applied to the electromagnet 14, and with a contact 30 in which an open-close state is changed in accordance with the fact that the armature 24 is attracted to the electromagnet 14, the iron core 20 is made to be displaceable in the direction of approaching to and separating from the armature 24, and an elastic member 22 which biases in the direction of separating from the armature 24 of the iron core 20 is installed. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a power relay, and more particularly to an AC power relay driven by an AC voltage.

  The power relay performs an opening / closing operation of a contact by attracting an armature by an electromagnetic force generated when a voltage is applied to an electromagnet. When operating the power relay (when attracting the armature by energizing the electromagnet), it is necessary to attract the armature from a state where the electromagnet and the armature are separated from each other, so a relatively large voltage is applied to the electromagnet. It is necessary. On the other hand, in a state where the armature is attracted by the electromagnet, the armature is almost in contact with the electromagnet, so that the armature does not return until the voltage applied to the electromagnet is sufficiently lower than the voltage during operation. In the present application, a voltage required to attract the armature to the electromagnet is referred to as an operating voltage, and a voltage at which the armature returns is referred to as a return voltage.

  By the way, the power relay includes an AC power relay and a DC power relay, and among these, the AC power relay is widely used for a control device of a manufacturing facility. In this AC power relay, the attracting force of the armature by the electromagnet fluctuates in synchronization with the amplitude change of the AC current flowing through the electromagnet. In order to suppress such fluctuations in the attractive force, it is common to provide an electromagnetic coil called a bear coil at the tip of the core of the electromagnet. However, even if a bear coil is provided, fluctuations in the attractive force cannot be completely prevented, and the armature constantly vibrates with the fluctuations in the attractive force. For this reason, in an AC power relay, the armature is restored only when the applied voltage to the electromagnet is relatively reduced from the operating voltage (that is, the difference between the operating voltage and the restoring voltage is reduced). Become.

Note that Patent Literature 1 and Patent Literature 2 are cited as literatures relating to relays. The invention disclosed in Patent Document 1 prevents the core from buckling even if the height of the core is adjusted by crushing during the assembly process. The invention disclosed in Patent Document 2 relates to a relay control circuit that makes it possible to reduce current and voltage required for an electromagnetic relay by using a bistable relay.
Japanese Patent No. 2920996 Japanese Patent No. 2620536

  Usually, in an AC power relay, a commercial power supply is used as an AC applied voltage to an electromagnet. However, the commercial power supply may experience a phenomenon in which the voltage drops instantaneously (instantaneous drop) due to various external factors. As described above, since the AC power relay is easy to recover from the operating state even with a relatively small voltage drop, the AC power relay unexpectedly recovers when the instantaneous drop occurs and is controlled by the AC power relay. May malfunction or the power may be cut off. Such a problem cannot be solved by the invention described in Patent Document 1. Further, in the invention of Patent Document 2, a dedicated control circuit is required, and the configuration becomes complicated.

  The present invention has been made in view of the above points, and an object of the present invention is to realize an AC power relay that is not easily affected by a drop in power supply voltage such as an instantaneous drop with a simple configuration.

In order to achieve the above object, the present invention provides an electromagnet in which an electromagnetic coil is wound around an iron core, an armature attracted by the electromagnet when an AC voltage is applied to the electromagnet, and the armature. An AC power relay comprising a contact that changes an open / close state in response to being attracted by the electromagnet,
The iron core is configured to be displaceable in a direction toward and away from the armature, and urging means for urging the iron core in a direction away from the armature is provided.

  According to the present invention, since the iron core is displaceable in a direction toward and away from the armature, and biasing means for biasing the iron core in the direction away from the armature is provided, voltage is applied to the electromagnet. In a return state where no voltage is applied, the iron core is separated from the armature, and in an operating state where a voltage is applied to the electromagnet, the iron core approaches the armature due to magnetic attraction. Here, the AC power relay has a characteristic that the operating voltage and the return voltage are lower as the distance between the iron core and the armature is smaller. Therefore, according to the present invention, it is possible to realize an AC power relay that is less susceptible to the influence of a power supply voltage drop such as a momentary drop by raising the operating voltage and lowering the return voltage.

  In the present invention, there may be provided restricting means for restricting a displacement of the iron core in a direction away from the armature at a predetermined position. Moreover, you may comprise so that viscous resistance may act on the said iron core according to the displacement of the said iron core.

  ADVANTAGE OF THE INVENTION According to this invention, the alternating current power relay which is hard to receive the influence of power supply voltage drops, such as a momentary drop, is realizable with the simple structure which made the iron core of the electromagnetic coil movable.

  FIG. 1 is a cross-sectional view of an AC power relay 10 according to an embodiment of the present invention. As shown in the figure, the AC power relay 10 of this embodiment includes a yoke 12 having an L-shape when viewed from the side, and an electromagnet 14. The electromagnet 14 includes an electromagnetic coil 16 and an iron core 20 inserted inside a bobbin 18 around which the electromagnetic coil 16 is wound. The bobbin 18 is fixed to the first arm portion 12 a of the yoke 12. On the other hand, the iron core 20 is configured to be vertically movable with respect to the bobbin 18. In addition, interference with the iron core 20 and the yoke 12 is prevented by forming the opening part 21 in the position corresponding to the iron core 20 of the 1st arm part 12a of the yoke 12. FIG. In addition, a viscous fluid such as grease is interposed between the outer peripheral surface of the iron core 20 and the inner peripheral surface of the bobbin 18 so that a viscous resistance is generated when the iron core 20 is displaced.

  An elastic member 22 such as a leaf spring is provided between the lower end of the iron core 20 and the lower surface of the first arm portion 12 a of the yoke 12. The elastic member 22 urges the iron core 20 downward in the figure by its elastic force. Further, a stopper portion 23 projecting sideways is provided in the vicinity of the upper end portion of the iron core 20, and as shown in FIG. 1, the stopper portion 23 comes into contact with the upper end surface of the bobbin 18, thereby The downward displacement in the figure is restricted.

  An armature 24 is supported on the upper end portion of the second arm portion 12b of the yoke 12 in the figure. The armature 24 extends rightward in the drawing to a position facing the tip of the iron core 20 and receives a magnetic attraction force by the electromagnet 14, and an operation portion 24b that opens and closes a contact point to be described later. It is a letter-shaped member and is supported by the upper end part of the 2nd arm part 12b of the yoke 12 in the bending part. A first contact piece 26 is attached to the outside of the second arm portion 12 b of the yoke 12 with a predetermined interval, and the armature 24 is interposed between the second arm portion 12 b and the first contact piece 26. An operating part 24b is arranged. Further, a second contact piece 28 is attached at a predetermined interval from the first contact piece 26, and a contact 30 is provided on the first contact piece 26 and the second contact piece 28.

  The first contact piece 26 is made of a leaf spring material. When no voltage is applied to the electromagnet 14, the operating portion 24 b of the armature 24 is moved by the spring force of the first contact piece 26 as shown in FIG. 1. It is urged in a direction to be pressed against the second arm portion 12b (that is, in a direction in which the action portion 24a of the armature 24 is separated from the electromagnet 14). In this state, the first contact piece 26 and the second contact piece 28 are separated from each other, and the contact 30 is in a break state.

  At the upper end portion of the iron core 20, a bear removing coil 32 is provided. An alternating current that constantly changes flows through the electromagnet 14, and the bear coil 32 is provided for the purpose of preventing the armature 24 from being opened due to a decrease in attractive force during a short period of time when the current decreases. However, as described above with respect to the above-mentioned prior art, it is impossible to sufficiently stabilize the attractive force of the armature 24 and to lower the return voltage by using only the darkening coil 32.

Next, the operation of the AC power relay 10 of this embodiment will be described.
In a state where no voltage is applied to the electromagnet 14, no electromagnetic attractive force acts on the action portion 24 a of the armature 24. For this reason, as shown in FIG. 1, the actuating portion 24 b of the armature 24 urges the first piece 26 toward the yoke 12, the acting portion 24 a is separated from the electromagnet 18, and the first piece 26 and the second piece The section 28 is separated and the contact point 30 is opened (break state). In this state, the iron core 20 is urged downward by the elastic member 22 and is at the lowest position in the vertical movable range.

  On the other hand, when a voltage is applied to the electromagnet 14, a large electromagnetic attractive force by the electromagnet 14 acts on the action portion 24 a of the armature 24. Thereby, the action part 24a is attracted to the electromagnet 14 side, and the actuating part 24b drives the first contact piece 26 leftward in the drawing against the spring force of the first contact piece 26, thereby closing the contact 30. At this time, an upward attractive force in the drawing acts on the iron core 20 of the electromagnet 14. Here, the force with which the elastic member 22 urges the iron core 20 downward in the figure is designed to be smaller than the suction force acting on the iron core 20. For this reason, when a voltage is applied to the electromagnet 14, the iron core 20 tends to be displaced upward in the figure against the urging force of the elastic member 22. However, as described above, a viscous fluid such as grease is interposed between the iron core 20 and the bobbin 18, and a large viscous resistance acts on the iron core 20. Therefore, immediately after the voltage is applied to the electromagnet 14, FIG. Thus, the iron core 20 is in the same position as in FIG. 1, and the tip of the iron core 20 and the action portion 24 a of the armature 24 are separated from each other. Thereafter, the iron core 20 is gradually displaced upward by the suction force acting on the iron core 20, and as shown in FIG. 3, the upper end stops at a position where it abuts against the action portion 24a of the armature 24, and the AC power relay. 10 becomes an operation state.

  When the voltage application to the electromagnet 24 is interrupted in the operation state shown in FIG. 3, the attractive force acting on the action part 24 a of the armature 24 disappears from the electromagnet 14, and at the same time, the upward suction in the figure acting on the iron core 20 Power also disappears. For this reason, the first piece 26 biases the operating portion 24b of the armature 24 toward the yoke 12 to open the contact 30, and the iron core 20 is displaced downward by the elastic force of the elastic member 22, Returning to the return state shown in FIG.

  As described above, in the AC power relay 10 of the present embodiment, in the return state shown in FIG. 1, the iron core 20 is at a position separated from the action portion 24 a of the armature 24, and in the operation state shown in FIG. 20 is displaced upward in the figure, and becomes a position close to the action portion 24 a of the armature 24. That is, in the return state where no voltage is applied to the electromagnet 14 (FIG. 1), the distance between the iron core 20 and the action portion 24a of the armature 24 is large, and in the operating state where the voltage is applied to the electromagnet 14 (FIG. 3). And the working portion 24a of the armature 24 become smaller.

  4 (a) and 4 (b) show a case where the distance between the iron core 20 and the action portion 24a of the armature 20 is large as shown in FIG. 1, and a case where the iron core 20 and the armature 24 are shown in FIG. When the distance to the action part 24a is small, the relationship between the ambient temperature and the operating voltage is indicated by a solid line, and the relationship between the ambient temperature and the return voltage is indicated by a broken line. 4A and 4B, both the operating voltage and the return voltage are higher when the distance between the iron core 20 and the action portion 24a of the armature 24 is larger. . Therefore, according to the AC power relay 10 of the present embodiment, the operating voltage becomes high as shown in FIG. 4A because the distance between the iron core 20 and the action portion 24a is large in the return state of FIG. In the operation state 3, since the distance between the iron core 20 and the action portion 24a is small, the return voltage is low as shown in FIG. That is, in this embodiment, the operating voltage is kept high as shown in FIG. 4A by changing the distance between the iron core 20 and the action portion 24a of the armature 24 between the operating state and the return state, The return voltage can be kept low as shown in FIG. Therefore, according to the present embodiment, it is possible to realize the AC power relay 10 that has a large difference between the operating voltage and the return voltage, and is thus less susceptible to the power supply voltage drop.

  In addition, although the said embodiment demonstrated the case where this invention was applied to the AC power relay of a specific form as shown in FIG. 1, the form of the AC power relay which can apply this invention is limited to these. It can be applied to various forms of AC power relays. In short, an AC power having an electromagnet, an armature that is attracted to the electromagnet when an AC voltage is applied to the electromagnet, and a contact that changes an open / close state in accordance with the attraction of the armature to the electromagnet Widely applicable to relays.

It is sectional drawing of the alternating current power relay which is one Embodiment of this invention, and shows the return state of an alternating current power relay. It is sectional drawing which shows the state immediately after the alternating current power relay of this embodiment switched to the operation state. It is sectional drawing which shows the steady operation state of the alternating current power relay of this embodiment. 4 (a) and 4 (b) show the relationship between the ambient temperature and the operating voltage with a solid line when the distance between the iron core and the working part of the armature is large and when the distance is small. The relationship between the temperature and the return voltage is indicated by a broken line.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 AC power relay 12 Relay 12a 1st arm part 12b 2nd arm part 14 Electromagnet 16 Electromagnetic coil 18 Bobbin 20 Iron core 21 Opening part 22 Elastic member 23 Stopper part 24 Armature 24a Action part 24b Actuation part 26 First contact piece 28 Second contact piece 30 Contact point 32 Bear coil

Claims (3)

An electromagnet in which an electromagnetic coil is wound around an iron core, an armature attracted to the electromagnet when an AC voltage is applied to the electromagnet, and an open / closed state according to the armature being attracted to the electromagnet An AC power relay comprising a contact for changing
AC power characterized in that the iron core is configured to be displaceable in a direction toward and away from the armature, and provided with a biasing means for biasing the iron core in a direction away from the armature. relay.   2. The AC power relay according to claim 1, further comprising a restricting means for restricting a displacement of the iron core in a direction away from the armature at a predetermined position. The AC power relay according to claim 1, wherein a viscous resistance acts on the iron core in accordance with the displacement of the iron core.

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