JP4277667B2 - Release electromagnetic solenoid - Google Patents

Description

  The present invention relates to a release-type electromagnetic solenoid applied to a tripping device such as a circuit breaker for wiring and a circuit breaker.

The circuit breaker mentioned above is equipped with an overcurrent trip device, an earth leakage trip device, or a voltage trip device of an attached device, and the trip circuit is operated by a trip signal. This tripping device uses a plunger-type electromagnetic solenoid, and the release operation thereof strikes the trip cross bar of the opening / closing mechanism to release the latch, thereby opening the main circuit contact.
Here, FIG. 3 shows the configuration of a circuit breaker taking an earth leakage breaker as an example, and FIG. 4 shows the conventional configuration of a release electromagnetic solenoid applied to the tripping device. In FIG. 3, 1 is a circuit breaker case having a two-part structure comprising a lower case 1a and an upper cover 1b, 2 is a stationary contact connected to the main circuit terminal, 3 is a movable contact, 4 is a toggle link 4a, and an open / close spring 4b. The toggle link type opening / closing mechanism, 5 is an operation handle, 6 is an overcurrent tripping device, 7 is an earth leakage trip unit built in the circuit breaker case 1, and the earth leakage trip unit 7 has a release shown in FIG. An electromagnetic solenoid 8 is incorporated.

This release electromagnetic solenoid 8 always holds a plunger energized by a release spring by a built-in permanent magnet at a suction position, and a release coil energized by receiving a trip signal applies a demagnetizing field to the permanent magnet. The plunger is released so that the plunger 9 is released. As shown in FIG. 4, the plunger 9, the release coil 10, the permanent magnet 11, the yoke 12, and the release spring 13 are combined. Although not shown, an operating member including a spring receiver 9a is coupled to the plunger 9, and the trip crossbar of the circuit breaker switching mechanism is hit through the operating member when the electromagnetic solenoid is released. Yes.
Here, the release coil 10 is wound around a cylindrical coil winding frame 10a which is a resin molded product. The yoke 12 is a combination of a U-shaped frame 14 obtained by bending a magnetic plate material (steel plate) and a flat frame 15 spanned between upper end side leg portions of the frame 14 to form a release coil 10 and a permanent magnet 11. A common magnetic circuit is configured. A block-shaped permanent magnet 11 magnetized in the vertical (thickness) direction is superimposed on the bottom surface of the U-shaped frame 14 with the magnetic pole surface (S pole) facing downward, A pole piece 16 is stacked and interposed under the release coil 10.

The plunger 9 is a cylindrical body of ferromagnetic material, and is inserted into the inside of the coil winding frame 10a of the release coil 10 through a through hole 15a opened (burring) in the center of the flat frame 15 of the yoke 12. A release spring (compression spring) 13 is inserted between the flange-shaped spring receiver 9a provided at the end of the shaft protruding upward from the yoke 12 and the upper surface of the yoke, and the plunger 9 is released in the release direction (arrow P). Spring is energized. Reference numeral 17 denotes a plunger guide made of a non-magnetic material (copper) fitted on the inner periphery of the coil winding frame 10a, and the plunger 9 guides and supports the plunger 9 so as to be slidable up and down.
With the above configuration, when the circuit breaker is reset and the plunger 9 is pushed into the illustrated standby position, the plunger 9 is attracted and held at this position by the magnetic force of the permanent magnet 11 while the release spring 13 is stored. Is done. In this attracting and holding state, the magnetic flux φm emitted from the N pole of the permanent magnet 11 returns to the S pole through a route passing through the pole piece 16, the plunger 9 and the yoke 12. F2 is greater than F1 (F2> F1), where F1 is the spring force of the release spring 13 and F2 is the magnetic attractive force of the permanent magnet 9.

On the other hand, when a leakage current flows through the main circuit of the circuit breaker shown in FIG. 3 in this state and an excitation current is supplied to the release coil 10 by a signal from the leakage detection circuit that detects this, the magnetomotive force (ampere turn) of the coil is detected. ), A magnetic field is generated in a direction that cancels the magnetic force of the permanent magnet 11, and the magnetic flux φi flows in a direction opposite to the magnetic flux φm of the permanent magnet 11 through a route passing through the yoke 12, the plunger 11, and the permanent magnet 11. As a result, the magnetic attractive force acting on the plunger 9 is reduced, and the plunger 9 is projected to the release position by the stored spring force of the release spring 13 to trip the circuit breaker.
By the way, in the electromagnetic solenoid having the above configuration, the magnetic flux φi generated by energization of the release coil 10 passes through the permanent magnet 11 (generally, the permeability of the permanent magnet made of a magnet material is much smaller than that of a magnetic core material such as a steel plate). Therefore, the magnetic resistance of the magnetic circuit viewed from the release coil 10 is increased. For this reason, since the magnetomotive force required for the release coil 10 is increased and the number of coil turns is increased, the size of the coil, and hence the electromagnetic solenoid, is increased.

On the other hand, for a release-type electromagnetic solenoid similar to that described above, a ring-shaped permanent magnet is used as the permanent magnet that attracts and holds the plunger, and the plunger is inserted into the ring-shaped permanent magnet so that the magnetic flux generated by energizing the release coil. φi passes through the yoke directly from the plunger without going through the permanent magnet, and the permanent magnet is combined with a pole piece called “pole shoe” so as to confront the outer peripheral surface of the plunger, and the permanent magnet and plunger The thing of the structure which formed the magnetic circuit between these is known (for example, refer patent document 1).
According to this configuration, since the magnetic flux of the release coil passes through a route that bypasses the permanent magnet, the magnetic resistance of the magnetic circuit viewed from the coil is reduced. Therefore, since the magnetomotive force required for the release coil is smaller than that of the electromagnetic solenoid shown in FIG. 4, it is possible to reduce the size by reducing the number of coil windings accordingly.
JP 2001-35344 A

As described above, the electromagnetic solenoid of the tripping device mounted on the circuit breaker can be manufactured in a small and low cost with as few parts and assembly man-hours as possible, and stable suction and release operation and high reliability in terms of operation. It is desirable to be able to ensure the property.
Therefore, the inventors replaced the block-shaped permanent magnet 11 employed in the conventional electromagnetic solenoid shown in FIG. 4 with a ring-shaped permanent magnet and a pole shoe as disclosed in Patent Document 1 above. As a result of studying from various angles with the goal of replacing and commercializing, the following problems to be solved were identified in terms of structure and function. That is,
(1) In order to assemble the release coil and ring-shaped permanent magnet inside the yoke in place, it is desirable that the assembly structure for holding the parts in place is simple and that the number of parts is small. It is.
In this regard, in the structure of Patent Document 1 in which a pole shoe is combined with a ring-shaped permanent magnet disposed on the inner peripheral side of the release coil and opposed to the peripheral surface of the plunger, the outer diameter of the release coil is increased. The number of parts increases and the assembly structure becomes complicated.

(2) Further, as shown in FIG. 4, when the inner peripheral surface of the through hole 15a opened in the flat frame 15 of the yoke 12 and the plunger 9 passing through the hole are directly facing each other with a play gap, The plunger 9 is offset by the magnetic attraction force of the magnetic flux passing through the portion and is directly attracted to the inner peripheral surface of the through hole 15a. For this reason, the load applied to the movement of the plunger 9 increases, and the suction and release characteristics of the electromagnetic solenoid become unstable.
(3) Furthermore, in the circuit breaker, dust generated foreign matter is generated in the arc extinguishing chamber due to the high-temperature arc generated when the current is interrupted, and this generated foreign matter diffuses throughout the circuit breaker case. In this case, if the generated foreign material enters and adheres to the gap between the electromagnetic solenoid plunger and the yoke and the coil winding frame of the release coil, the plunger moves and the plunger moves smoothly. In addition, if the generated foreign material accumulates on the bottom surface of the yoke facing the tip of the plunger, the permanent magnet's attractive force may not sufficiently act on the plunger, causing malfunctions such as the plunger being released unexpectedly. There is.

In this respect, as shown in FIG. 4, in the structure in which the plunger 9 having the columnar shape (the same overall length and the same diameter) is inserted into the space surrounded by the yoke 12 and the coil winding frame 10a of the release coil, the reset is performed. , Since the volume of gas in the space changes greatly with the movement of the plunger 9 during the release operation, it is easy to suck dust-like generated foreign matter into the space (plunger moving space) from the periphery through the gap. . Further, when looking at the gap between the through hole 15a opened in the flat frame 15 of the yoke 12 and the peripheral surface of the plunger 9, the gap length in the circumferential direction increases as the shaft diameter of the plunger passing through the through hole increases. The dust becomes larger and the dusty generated foreign matter easily enters.
The present invention has been made in view of the above points, and an electromagnetic solenoid for tripping a circuit breaker improved so as to achieve low cost and high reliability by simplifying the assembly structure and stabilizing the release operation. Is to provide.

To achieve the above object, according to the present invention, when there is no trip signal, the permanent magnet attracts and holds the plunger in the suction position against the release spring, and receives the trip signal to energize the release coil. A release type electromagnetic solenoid that applies a demagnetizing field to a permanent magnet to release a plunger is configured as follows. That is,
The electromagnetic solenoid is spanned between a release coil wound around a coil winding frame that becomes a resin-molded product, a ring-shaped permanent magnet arranged coaxially with the release coil, and a U-shaped frame and a leg of the frame. A yoke that surrounds the release coil and the permanent magnet by combining a flat frame, and a front end face the bottom surface of the U-shaped frame through the inside of the release coil and the permanent magnet, and a shaft portion on the rear end side It is an assembly of a plunger protruding outward through a through-hole opened in the flat frame and a release spring that urges the plunger toward the release position, and the coil winding frame of the release coil includes A cylindrical magnet support guide that extends in the axial direction from the end portion and fits and holds a ring-shaped permanent magnet is integrally formed (claim 1).

Moreover, there exists the following structures as an embodiment of the said structure.
(1) As the permanent magnet, a permanent magnet magnetized in the axial direction of the ring so that the upper and lower end surfaces thereof are N and S poles is used.
(2) As the permanent magnet, a permanent magnet that is magnetized in the radial direction so that the inner and outer peripheral surfaces of the ring are N and S poles is used.
(3) A cylindrical plunger guide made of non-magnetic material is provided inside the through hole opened in the yoke flat frame, and the plunger guide is slidably supported by the plunger guide as a sliding bearing. (Claim 4).
(4) The plunger guide described in the preceding item (3) is formed integrally with the coil winding frame of the release coil so as to extend from the end in the axial direction (Claim 5).

  (5) The plunger has a stepped structure in which the shaft diameter of the rear end side shaft portion is smaller than that of the plunger tip portion, and the rear end side small diameter shaft portion is removed through a through hole opened in a flat frame of the yoke. (Claim 6).

By configuring the release electromagnetic solenoid for tripping mounted on a circuit breaker as described above, the following effects can be obtained.
(1) A ring-shaped magnet support guide extending in an axial direction from an end portion of the release coil and axially holding a ring-shaped permanent magnet is integrally formed with the ring. Can be assembled together with the release coil at a fixed position inside the yoke by inserting and inserting the permanent magnet into the coil winding frame, thereby reducing the number of parts and assembly man-hours. Solenoid can be assembled. Moreover, the permanent magnet is provided with a pole piece because the magnetic pole surface magnetized on the upper end surface or inner peripheral surface of the ring magnet is opposed to the peripheral surface of the plunger without going through the pole piece. It is possible to reduce the number of parts and reduce the size of the electromagnetic solenoid while demonstrating a magnetic attractive force comparable to the case.

(2) A plunger guide made of non-magnetic material is provided inside the through hole opened in the yoke flat frame, and the plunger guide is slidably guided and supported by using the plunger guide as a sliding bearing. According to the fourth aspect of the present invention, it is possible to avoid a problem (increase in load load) in which the plunger that has passed through the through hole of the yoke is offset and adsorbed to the yoke, and the plunger guide Since the guide is supported so that it can slide smoothly, a stable release characteristic can be secured and reliability can be improved.
(3) According to the configuration of claim 5, the plunger guide of the preceding item (2) is formed integrally with the coil winding frame of the release coil so as to extend in the axial direction from the end thereof. Costs can be reduced by reducing man-hours.
(4) Further, the plunger has a stepped structure in which the shaft diameter of the rear end side of the plunger is smaller than the diameter of the plunger tip, and the small diameter shaft on the rear end side is passed through a through hole opened in a flat frame of the yoke. According to the configuration of the sixth aspect of the present invention, the space inside the solenoid (the yoke, the release coil coil frame, and the ring-shaped permanent magnet enclosed by the movement of the plunger accompanying the reset and release operation is drawn. The change in gas volume in the plunger movement space is smaller than that of a conventional cylindrical plunger. Thereby, it can suppress that the generated foreign material which generate | occur | produced in the circuit breaker case with the electric current interruption of a circuit breaker penetrate | invades into the said plunger movement space from the circumference | surroundings. In addition, by reducing the shaft diameter of the rear end side shaft of the plunger, the through hole opened in the flat frame of the yoke also has a small diameter, and the gap length with the plunger is reduced. As compared with the conventional structure, the generated foreign matter is less likely to enter.

  DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below based on the examples shown in FIGS. In the drawings of the respective embodiments, the same reference numerals are given to members corresponding to those in FIG. 4 and description thereof is omitted.

FIG. 1 shows an embodiment of an electromagnetic solenoid corresponding to claims 1, 2, 4 and 6 of the present invention.
In the electromagnetic solenoid 8 of this embodiment, a ring-shaped permanent magnet 18 is employed in place of the block-shaped permanent magnet 11 in FIG. 4. In the illustrated attracting state, the plunger 9 is connected to the ring-shaped permanent magnet 18. It is inserted into the hollow portion, and its front end surface is abutted against the bottom surface of the U-shaped frame 14 of the yoke 12 so as to be sucked and held at this position. The permanent magnet 18 is magnetized in the height direction (the axial direction of the ring-shaped magnet) so that the upper surface is an N pole and the lower surface is an S pole.
Here, the permanent magnet 18 is formed integrally with the coil winding frame (resin mold product) 10a of the release coil 10 and is provided on the outer peripheral side of the cylindrical magnet support guide 10a-1 extending downward from the lower end thereof. It is inserted and held in place.

The plunger 9 fitted in the space surrounded by the coil winding frame 10a and the yoke 12 has a tip portion 9b (shaft diameter: d1) having a large diameter in the longitudinal direction and a small diameter rear portion as shown in the drawing. It has a stepped structure in which an end-side shaft portion 9c (shaft diameter: d2) is formed, and a small-diameter shaft portion 9c protrudes to the outside through a through-hole drilled in a flat frame 15 arranged on the upper surface side of the yoke 12. .
Furthermore, in this embodiment, a plunger having a cylindrical shape with a hook made of a non-magnetic material made of copper or resin and having a small friction coefficient is formed on the inner peripheral surface of the through hole drilled in the flat frame 15. A guide 19 is provided, and the shaft portion 9c of the plunger 9 passed through the through hole of the yoke via the plunger guide 19 is slidably guided and supported.
In the above configuration, when the plunger 9 is pushed into the illustrated standby position by the reset operation of the circuit breaker, it is attracted and held at this position by the magnetic force of the ring-shaped permanent magnet 18. In this state, the magnetic flux φm of the permanent magnet 18 exits from the N pole and enters the peripheral surface of the large-diameter tip portion 9b of the plunger 9 and passes through the bottom surface of the U-shaped frame 14 of the yoke 12 from the tip surface. Then, the route returns to the south pole of the permanent magnet 18.

In this state, when the release coil 10 is energized by the trip signal, the magnetic flux φi flows from the yoke 12 to the route via the plunger 9 so as to cancel the magnetic force of the permanent magnet 18. In this case, the magnetic flux .phi.i bypasses the permanent magnet 18 as shown in the drawing and directly enters the distal end portion 9b of the plunger 9 from the bottom surface of the U-shaped frame 14 of the yoke 12, and the nonmagnetic plunger from the shaft portion 9c. It passes through a closed loop route that returns to the flat frame 15 of the yoke 12 via the guide 19. Therefore, the magnetic path resistance of the magnetic flux φi viewed from the release coil 10 is smaller than that of the configuration shown in FIG. 4 (the magnetic flux φi passes through the permanent magnet 11 having a low magnetic permeability), and the amount required for the release coil 10 is accordingly increased. Since the magnetic force, and therefore the number of coil turns, can be reduced, the size can be reduced.
In addition, since the plunger guide 19 is provided on the inner peripheral surface of the through hole of the flat frame 15 of the yoke 12 so as to guide and support the plunger 9, it is possible to prevent the plunger from adsorbing which is a problem in the conventional configuration. A stable release operation can be ensured by avoiding.

  Furthermore, since the shape of the plunger 9 is a stepped structure as described above, the plunger 9 moves in the space surrounded by the coil frame 10a and the yoke 12 in accordance with the reset and release operations of the electromagnetic solenoid. In doing so, the change in the volume of gas in the space is smaller than that of the cylindrical plunger shown in FIG. That is, considering the case where the plunger 9 protrudes and moves in the direction of the arrow P from the illustrated standby position by the release operation of the electromagnetic solenoid, the small-diameter shaft portion 9c of the plunger 9 and the coil winding frame 10a surrounding the moving space Since the gas (air) that filled the gap between the two ends up around the gap formed between the bottom surface of the yoke 12 and the tip 9b of the plunger 9 as the plunger 9 moves upward, The gas volume change is small. As a result, the amount of foreign matter (dust-like generated foreign matter generated and diffused by an arc associated with current interruption of the circuit breaker) that is sucked into the space from the surroundings and deposited on the bottom surface of the yoke 12 is reduced. Regardless of use, the plunger 9 can be stably attracted and held in the illustrated standby position by the magnetic force of the permanent magnet 18. Similarly, since the shaft diameter d2 of the plunger shaft 9c drawn out through the through hole of the flat frame 15 of the yoke 12 is small, the gap length of the through hole is also small, and it is difficult for foreign matter to enter from the outside. As a result, an unexpected release malfunction caused by dusty foreign matter entering the space from the surroundings is prevented, and the reliability of the electromagnetic solenoid is improved.

  In the assembly process of the electromagnetic solenoid 8, a ring-shaped permanent magnet 18 is fitted and held in the magnet support guide 10a-1 of the coil winding frame 10a around which the release coil 10 is wound, and this assembly is then used as the yoke 12. It fits in the U-shaped frame 14. On the other hand, after inserting the shaft portion 9c of the plunger 9 from the lower side into the flat frame 15 having the nonmagnetic plunger guide 19 attached to the through hole, the spring receiver 9a and the release spring 13 are assembled on the upper surface side. . Then, the flat frame 15 of this assembly is overlapped with the upper end of the U-shaped frame 14 of the assembly and screwed. Thereby, the electromagnetic solenoid 8 can be assembled with a small number of parts and assembly man-hours.

  Next, FIG. 2 shows a configuration of an embodiment corresponding to claims 1, 3, 5 and 6 of the present invention. In this embodiment, compared to the first embodiment, the ring-shaped permanent magnet 18 is magnetized in the radial direction of the ring so that the inner and outer peripheral surfaces thereof are N and S poles. Further, the coil winding frame 10a of the release coil 10 extends from the lower end portion thereof to a cylindrical magnet support guide 10a-1 for inserting and holding the ring-shaped permanent magnet 18, and from the upper end side of the winding frame. A cylindrical plunger guide 10a-2 that extends upward and fits into a gap between a shaft portion 9c of the plunger 9 and a through hole opened in the flat frame 15 of the yoke 12 is integrally formed. . That is, since the ring-shaped permanent magnet 18 and the plunger guide 19 of the independent part shown in FIG. 1 can be integrated with the coil winding frame 10a to be a resin molded product as a base, the number of parts can be increased as compared with the first embodiment of FIG. Reduction can be achieved. The electromagnetic solenoid 8 of this embodiment is slightly different from the assembly procedure of the first embodiment, and the shaft portion of the plunger 9 is in a stage before the coil winding frame 10a of the release coil 10 is fitted into the yoke U-shaped frame 14. 9c is passed through the coil winding frame 10a from below.

Cross-sectional view of a configuration of an electromagnetic solenoid corresponding to Example 1 of the present invention Cross-sectional view of an electromagnetic solenoid corresponding to Example 2 of the present invention Overall configuration of circuit breaker equipped with electromagnetic solenoid for tripping Sectional view of the conventional configuration of the tripping solenoid installed in the circuit breaker of FIG.

Explanation of symbols

8 Electromagnetic solenoid 9 Plunger 9b Front end 9c Rear end shaft 10 Release coil 10a Coil winding frame 10a-1 Magnet support guide 10a-2 Plunger guide 12 yoke 13 Release spring 14 U-shaped frame 15 of yoke Flat frame 15a through hole 18 ring-shaped permanent magnet 19 plunger guide

Claims (6)

When there is no trip signal, the permanent magnet attracts and holds the plunger at the suction position against the release spring, and the release coil that receives the trip signal and energizes gives a demagnetizing field to the permanent magnet to release the plunger. In the release-type electromagnetic solenoid,
An electromagnetic solenoid is bridged between a release coil wound around a coil winding frame that is a resin-molded product, a ring-shaped permanent magnet arranged coaxially with the release coil, and a U-shaped frame and a leg of the frame. A yoke that surrounds the release coil and the permanent magnet by combining a flat frame, and a front end face the bottom surface of the U-shaped frame through the inside of the release coil and the permanent magnet, and a shaft portion on the rear end side It is an assembly of a plunger protruding outward through a through-hole opened in the flat frame and a release spring that urges the plunger toward the release position, and the coil winding frame of the release coil includes A release-type electromagnetic solenoid characterized by integrally forming a cylindrical magnet support guide that extends in an axial direction from an end portion and fits and holds a ring-shaped permanent magnet. The electromagnetic solenoid according to claim 1, wherein the ring-shaped permanent magnet is magnetized in the axial direction thereof. 2. The electromagnetic solenoid according to claim 1, wherein the permanent magnet is magnetized in a radial direction of the ring. 2. The electromagnetic solenoid according to claim 1, wherein a cylindrical plunger guide made of a non-magnetic material is provided inside a through hole opened in the flat frame of the yoke, and the plunger guide is used as a sliding bearing. A release-type electromagnetic solenoid characterized in that it is slidably guided and supported. 5. The electromagnetic solenoid according to claim 4, wherein the plunger guide is formed integrally with the coil winding frame of the release coil so as to extend from the end thereof in the axial direction. 6. The electromagnetic solenoid according to claim 1, wherein the plunger has a stepped structure in which the shaft diameter of the rear end side shaft portion is smaller than that of the plunger tip portion. .

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