JP2005340703A - Release type electromagnetic solenoid - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a stabilized sucking force by preventing the sucking force from lowering due to reduction in pole contact area while preventing a variation in the holding force of a permanent magnet caused by the inclination of a movable contact or the like. <P>SOLUTION: This release type electromagnetic solenoid comprises a movable contact 9 moving in a spool 10a around which an exciting coil 10 is wound, a fixed contact 18 provided on one surface of a yoke 12, and a ring-like permanent magnet 19 for holding a trip spring 13 in an energy storing state wherein the pole contact face of the fixed contact 18 facing the forward end face of the movable contact 9 is a spherical contact face 18a formed with a recess 18b in the center. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a release electromagnetic solenoid used in a tripping device for a circuit breaker such as a circuit breaker for wiring or a leakage breaker.

The circuit breaker mentioned above detects when an abnormal current such as overload current or leakage current flows in the main circuit, and detects the trip corros bar of the switching mechanism of the circuit breaker based on the detected signal. A tripping device is provided that trips the latch to strike and open the main circuit. In recent years, a release electromagnetic solenoid has been increasingly used as the tripping device.
Hereinafter, a conventional circuit breaker and a release electromagnetic solenoid will be described with reference to the drawings.
FIG. 4 is an overall configuration diagram showing an example of a conventional circuit breaker, and FIG. 5 is a release electromagnetic solenoid having a conventional structure applied to the tripping device of FIG.
In FIG. 4, 1 is a circuit breaker case having a two-part structure composed of a lower case 1a and an upper cover 1b, 2 is a fixed contact connected to the main circuit terminal, 3 is a movable contact, 4 is a toggle link mechanism 4a, and an open / close spring 4b. , An opening / closing mechanism unit including a latch 4c and a trip cross bar 4d, 5 an operation handle, 6 an overcurrent tripping device, and 7 an earth leakage trip unit built in the circuit breaker case 1, and this earth leakage trip unit 7 The release type electromagnetic solenoid 8 shown in FIG.

In this release-type electromagnetic solenoid 8, an exciting coil that is normally energized by receiving a trip signal and holding a movable contact as a plunger urged by a tripping spring by a built-in permanent magnet at a suction position. A demagnetizing field is applied to the magnet to release the movable contact. As shown in FIG. 5, each of the movable contact 9, the exciting coil 10, the permanent magnet 11, the yoke 12, and the tripping spring 13 is provided. The configuration is a combination of parts. Although not shown, an operation member including a spring receiver 9a is coupled to the movable contact 9, and the trip crossbar of the opening / closing mechanism portion of the circuit breaker is hit through the operation member when the electromagnetic solenoid is released. I have to.
Here, the exciting 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 an exciting 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, The fixed contact 16 is overlapped and interposed under the exciting coil 10.

Further, the movable contact 9 is a cylindrical body made of a ferromagnetic material, and is inserted into the inside of the coil winding frame 10a of the exciting coil 10 through a through hole 15a opened (burring process) in the center of the flat frame 15 of the yoke 12. The movable contact 9 is released in the release direction (arrow) by inserting a tripping spring (compression spring) 13 between a hook-shaped spring receiver 9a provided on the shaft end protruding upward from the yoke 12 and the upper surface of the yoke. P) is spring-biased. Reference numeral 17 denotes a movable contact guide made of a non-magnetic material (copper) fitted on the inner periphery of the coil winding frame 10a, and the movable contact 9 is guided and supported by the guide so as to be vertically slidable.
With the above configuration, when the circuit breaker is reset and the movable contact 9 is pushed into the illustrated standby position, the movable contact 9 is moved to this position by the magnetic force of the permanent magnet 11 while the tripping spring 13 is stored. Is sucked in. 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 fixed contact 16, the movable contact 9 and the yoke 12. Note that F2 is greater than F1 (F2> F1), where F1 is the spring force of the tripping 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. 4 in this state and the excitation current is supplied to the excitation coil 10 with a signal from the leakage detection circuit that detects this, the magnetomotive force (ampere turn) of the coil is detected. ) Generates a magnetic field 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 movable contact 9, and the permanent magnet 11. . As a result, the magnetic attractive force acting on the movable contact 9 is reduced, and the movable contact 9 protrudes to the release position by the stored spring force of the tripping 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 exciting 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). For this reason, the magnetic resistance of the magnetic circuit viewed from the exciting coil 10 is increased. For this reason, since the magnetomotive force required for the exciting coil 10 is increased and the number of coil turns is increased, the size of the coil and thus the electromagnetic solenoid is increased.

On the other hand, as a release-type electromagnetic solenoid similar to the above, a ring-shaped permanent magnet is used, and a movable contact is inserted into the ring-shaped permanent magnet, and the bottom surface of the central portion of the yoke facing the movable contact With the side as a fixed contact, the magnetic flux φi generated by energizing the exciting coil passes directly from the movable contact without going through the permanent magnet, and the permanent magnet is combined with a pole piece called “pole shoe” There is also known a configuration in which a magnetic circuit is formed between a permanent magnet and a movable contact so as to face the outer peripheral surface of the movable contact (see, for example, Patent Document 1).
JP 2001-35344 A

By the way, the release type electromagnetic solenoid of the conventional structure described above repeats contact and separation between the movable contact and the stationary contact, and between the movable contact and the coil winding frame, between the movable contact and the yoke. The movable contact between the fixed contact and the tip of the movable contact is attracted while tilted in a state where it touches the fixed contact due to the play gap of the through hole opened in the flat frame. There is a drawback that the contact force easily changes due to a change in the contact area.
When the movable contact is tilted and attracted, the holding force of the permanent magnet due to the contact between the fixed contact and the tip of the movable contact decreases, and a stable attractive force cannot be obtained. There was a problem of malfunction due to vibration or the like.
In addition, in order to prevent a decrease in attractive force due to the inclination of the movable contact or the like, a spherical protrusion is formed on the bottom surface side of the central portion of the U-shaped magnetic frame or the end surface of the movable contact, and the movable contact is inclined. Japanese Unexamined Patent Publication No. 4-177709 discloses a release-type electromagnet device that always obtains a stable attractive force by making the contact always one point even when contact is made.

However, the release-type electromagnet device described in Japanese Patent Application Laid-Open No. 4-177709 has an armature compared to the case where no protrusion is provided because the contact between the movable contact and the fixed contact is always at one point. It is difficult to obtain an attractive force because the area is extremely reduced, and the magnetic flux density for obtaining the attractive force is usually reduced at the central part of the armature surface where the protrusions are formed due to the skin effect, etc. In order to obtain a stable attractive force, there is a drawback that the movable contact, the fixed contact and the permanent magnet have to be enlarged.
Accordingly, the object of the present invention is to prevent a change in the holding force of the permanent magnet due to the inclination of the movable contact, etc., and to prevent a reduction in the attractive force due to a decrease in the contact area, thereby obtaining a stable attractive force. An object of the present invention is to provide a release electromagnetic solenoid.

In order to solve the above problems, according to the present invention, a winding frame around which an exciting coil arranged in a yoke made of a magnetic material is wound, a fixed contact provided on one surface of the yoke, A movable contact that moves in the reel and contacts and separates from the fixed contact, a tripping spring that biases the movable contact in the direction of tripping, and holds the tripping spring in an energized state A release-type electromagnetic solenoid that applies a demagnetizing field to the permanent magnet by excitation of the excitation coil to release the movable contact, wherein a contact surface of the movable contact and the fixed contact At least one of them is a spherical positive surface having a depression at the center.
In the release electromagnetic solenoid, the permanent magnet may be a ring-shaped permanent magnet that is magnetized in the axial direction of the ring or magnetized in the radial direction of the ring.

Further, in the pre-release electromagnetic solenoid, a through hole through which the movable contact is inserted is formed in the yoke, and a movable contact guide made of a non-magnetic material is provided between the through hole and the movable contact. Alternatively, the movable contact guide may be formed integrally with the winding frame.
In the pre-release electromagnetic solenoid, a magnet support guide made of a non-magnetic material may be provided in the hollow portion of the permanent magnet, or the magnet support guide may be formed integrally with the winding frame.
Furthermore, the movable contact may have a stepped structure in which the shaft diameter of the rear end side shaft portion is smaller than that of the distal end portion of the movable contact.

  According to this invention, at least one of the armature surfaces of the movable contact and the stationary contact is a spherical armature surface in which a recess is formed in the center, so that the permanent magnet can be held due to the inclination of the movable contact or the like. A change in force can be prevented, a decrease in attractive force due to a decrease in the contact area can be prevented, and a stable attractive force can be obtained without increasing the size of the movable contact, the fixed contact and the permanent magnet.

Hereinafter, embodiments of the present invention will be described with reference to FIGS. In the drawings of the embodiments, members corresponding to those in FIG. 5 are denoted by the same reference numerals, and detailed description thereof is omitted.
FIG. 1 is a release type electromagnetic solenoid showing a first embodiment of the present invention. FIG. 1A is a sectional view of the configuration of the release type electromagnetic solenoid, and FIG. 1B is an enlarged view of a main part of a fixed contact portion in FIG. It is. In the figure, in the electromagnetic solenoid of the first embodiment, a ring-shaped permanent magnet 19 is arranged on the bottom surface of the U-shaped frame 14 of the yoke 12 instead of the block-shaped permanent magnet 11 in FIG. The permanent magnet 19 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.
A cylindrical fixed iron core (fixed contact) 18 is fixed to the center of the bottom surface of the U-shaped frame 14 of the yoke 12 by caulking or the like.

In the illustrated attracting state, the movable contact 9 is inserted into the hollow portion of the ring-shaped permanent magnet 19, and the tip surface of the movable contact 9 abuts against the contact surface of the fixed contact 18 so as to be attracted and held at this position. ing. Reference numeral 21 denotes a non-magnetic movable contact guide provided between the movable contact 9 and the reel 10a.
Here, in order to obtain a stable suction force by preventing a change in the holding force due to the inclination of the movable contact 9 and the like and a decrease in the suction force due to a decrease in the contact area, the contact surface of the movable contact 9 and the fixed contact 18 At least one of these is a spherical armature surface having a recess at the center.
In this embodiment, as shown in FIG. 1B, the contact surface 18a of the fixed contact 18 facing the front end surface of the movable contact 9 is slightly centered on the front end surface side of the movable contact 9. Is formed in a gentle spherical shape that protrudes, and an annular recess 18b is provided in the approximate center of the contact surface 18a.

In the above configuration, the operation of the release electromagnetic solenoid will be described first. When the movable contact 9 is pushed into the illustrated standby position by the reset operation of the circuit breaker, the movable contact 9 is fixed by the magnetic force of the ring-shaped permanent magnet 19. The contact 18 is sucked and held. Further, in this state, the magnetic flux φm of the permanent magnet 19 exits from the N pole and enters the peripheral surface of the movable contact 9, and passes through the fixed iron core 18 and the bottom surface of the U-shaped frame 14 of the yoke 12 from the front end surface. The route returns to the south pole of the permanent magnet 19.
In this state, when the exciting coil 10 is energized by the trip signal, the magnetic flux φi flows from the yoke 12 to the route via the fixed contact 18 and the movable contact 9 so as to cancel the magnetic force of the permanent magnet 19. In this case, the magnetic flux φi bypasses the permanent magnet 19 and enters the tip of the movable contact 9 through the fixed contact 18 from the bottom surface of the U-shaped frame 14 of the yoke 12 as shown in the figure. It follows a closed loop route that returns to the flat frame 15. Therefore, the magnetic path resistance of the magnetic flux φi viewed from the exciting coil 10 is smaller than that of the configuration shown in FIG. 5 (the magnetic flux φi passes through the permanent magnet 11 having a low permeability), and the magnetic flux resistance required for the exciting coil 10 is accordingly increased. Since the magnetic force, and therefore the number of coil turns, can be reduced, the size can be reduced.

Here, when the movable contact 9 is released from the state of FIG. 1 in the direction of the arrow P and then reset to the state of FIG. 1 again by a return mechanism (not shown), the movable contact 9 comes into contact with the fixed contact 18. In some cases, it may be adsorbed while tilted.
However, in this embodiment, the contact surface of the fixed contact 18 facing the tip surface of the movable contact 9 is a spherical contact surface 18a provided with a recess 18b in the center, so that the movable contact is possible. Even if the child 9 is tilted, the tip end surface of the movable contact 9 and the spherical contact surface 18a of the fixed contact 18 come into contact with each other, so that the contact between the fixed contact 18 and the movable contact 9 due to the inclination of the movable contact or the like. There is little change in the pole face, and a change in the holding force of the permanent magnet can be prevented.
Further, in the configuration in which only the protrusions are provided on the contact surface of the conventional structure, the contact surfaces of the movable contact and the fixed contact come into contact at one point, so that the contact in the contact state between the movable contact and the fixed contact is possible. Although the pole area is small and the suction force may be reduced, in this embodiment, when the normal movable contact 9 and the stationary contact 18 are in contact, the tip end surface of the movable contact 9 and the annular portion of the recess 18b Since the portions are in contact with each other, the contact area can be increased as compared with the conventional structure. Therefore, a stable attractive force can be obtained without increasing the dimensions of the fixed contact 18, the movable contact 9 and the permanent magnet 19, and a highly reliable release electromagnetic solenoid can be provided.

In the above embodiment, the spherical contact surface 18a provided with the recess 18b is formed on the fixed contact 18 fixed to the bottom surface of the U-shaped yoke 12. However, the contact surface 18a is You may make it form directly in the center part bottom face side of the yoke 12, and you may make it form in the front end surface side of the movable contact 9 instead of the stationary contact side.
Furthermore, the surface of the armature surface 18a is made flat, an annular recess is formed in the center of the armature surface 18a, and the armature surface of the movable or fixed contact facing the armature surface 18a is made spherical. You may do it.
Next, FIG. 2 shows a configuration of a release electromagnetic solenoid showing a second embodiment of the present invention. In this embodiment, the shape of the movable contact 91 in the winding frame is a stepped structure as compared with the first embodiment, and the magnet support guide 10a-1 and the movable contact are provided on the winding frame 10a of the exciting coil 10. The guide 10a-2 is formed integrally. As in the first embodiment, an annular recess 18b is provided at the center of the contact surface of the fixed contact 18 facing the tip surface of the movable contact 91.

According to this embodiment, even when a movable contact having a stepped structure is used, it is possible to prevent a reduction in attractive force due to a change in the holding force of the permanent magnet due to the inclination of the movable contact and a decrease in the contact area. Is.
In the figure, the movable contact 91 has a stepped structure in which a large diameter tip 91b and a small diameter rear end shaft 91c are formed in the longitudinal direction, and the small diameter shaft 9c is on the upper surface side of the yoke 12. The flat frame 15 disposed on the outside is configured to protrude to the outside through a through hole perforated.
Thus, when the movable contact 91 has a stepped structure, when the movable contact 91 moves in the space surrounded by the coil winding frame 10a and the yoke 12 in accordance with the reset and release operations of the electromagnetic solenoid. Changes in the gas volume in the space compared to the cylindrical movable contact shown in FIG. That is, considering the case where the movable contact 91 protrudes and moves from the illustrated standby position by the release operation of the electromagnetic solenoid, the space between the small-diameter shaft portion 91c of the movable contact 91 and the coil winding frame 10a surrounding the moving space is considered. Since the gas (air) filling the gap of the movable contact 91 wraps around the gap generated between the bottom surface of the yoke 12 and the tip 91b of the movable contact 91 as the movable contact 91 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 movable contact 91 can be stably attracted and held at the illustrated standby position by the magnetic force of the permanent magnet 19. Similarly, since the shaft diameter of the shaft portion 91c of the movable contact drawn out to the outside 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.

Further, the magnet support guide 10a-1 and the movable contact guide 10a-2 may be formed as a part made of a nonmagnetic material as a separate part from the coil winding frame 10a, but as shown in FIG. If the magnet support guide 10a-1 and the movable contact guide 10a-2 are integrally formed on the winding frame 10a of the exciting coil 10, the number of parts and the number of assembling steps can be reduced.
In the figure, the coil winding frame (resin mold product) 10a of the exciting coil 10 is integrally formed with a cylindrical magnet support guide 10a-1 as a spacer extending downward from the lower end thereof. The permanent magnet 19 is fitted on the outer periphery of the guide 10a-1 so as to be held at a fixed position.
Further, a cylindrical movable contact that extends upward from the upper end side of the winding frame 10a and fits into a gap between a shaft portion 91c of the movable contact 91 and a through hole opened in the flat frame 15 of the yoke 12. The guide 10a-2 is integrally formed, and the shaft portion 91c of the movable contact 91 passed through the through hole of the yoke is slidably guided and supported via the movable contact guide 10a-2. .

Such an electromagnetic solenoid assembling process includes inserting and holding the ring-shaped permanent magnet 19 in the magnet support guide 10a-1 of the coil winding frame 10a around which the excitation coil 10 is wound, and moving the movable contact to the coil winding frame 10a. The shaft portion 91c of 91 is passed from below, and this assembly is fitted into the U-shaped frame 14 of the yoke 12. Then, after inserting the shaft portion 91c of the movable contact 91 into the flat frame 15, the spring receiver 91a and the tripping 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.
According to the configuration of the above-described winding frame, the ring-shaped permanent magnet 19 and the movable contact guide 10a-2 can be integrated with the coil winding frame 10a that is a resin molded product as a base, so that the number of parts can be reduced and the number can be reduced. The electromagnetic solenoid can be assembled with the assembly man-hours.

Next, FIG. 3 shows a configuration of a release electromagnetic solenoid showing a third embodiment of the present invention. In this embodiment, compared to the second embodiment, the ring-shaped permanent magnet 19 is magnetized in the radial direction of the ring so that the inner and outer peripheral surfaces thereof are N-pole and S-pole. As in the second embodiment, an annular recess 18b is provided at the center of the armature surface of the stationary contact 18 facing the tip surface of the tip 91b of the movable contact 91.
Since other configurations are the same as those of the second embodiment, the same reference numerals are given and detailed descriptions thereof are omitted.
According to the above configuration, even when a permanent magnet magnetized in the radial direction of the ring is used, a change in the holding force of the permanent magnet due to the inclination of the movable contact and a reduction in the attractive force due to a decrease in the contact area are achieved. Can be prevented.

BRIEF DESCRIPTION OF THE DRAWINGS It is a release type electromagnetic solenoid which shows 1st embodiment of this invention, (a) is a structure sectional drawing of a release type electromagnetic solenoid, (b) is a principal part enlarged view of the stationary contact part of (a). Cross-sectional view of a release electromagnetic solenoid showing a second embodiment of the present invention Cross-sectional view of a release electromagnetic solenoid showing a third embodiment of the present invention Overall configuration diagram of a circuit breaker equipped with an electromagnetic solenoid for tripping Sectional drawing of the conventional configuration of the electromagnetic solenoid for tripping equipped in the circuit breaker of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 9 Movable contact 10 Excitation coil 10a Reel 10a-1 Magnet support guide 12 yoke 13 Tripping spring 18 Fixed iron core (fixed contact)
18a Contact surface 18b Recessed portion 19 Permanent magnet 21 Movable contact guide

Claims (8)

A winding frame wound with an exciting coil arranged in a yoke made of a magnetic material, a fixed contact provided on one surface of the yoke, and a contact with the fixed contact by moving in the winding frame A movable contact that opens, a tripping spring that urges the movable contact in the tripping direction, and a permanent magnet that holds the tripping spring in a stored state. In a release electromagnetic solenoid that applies a demagnetizing field to a permanent magnet to release the movable contact,
A release-type electromagnetic solenoid characterized in that at least one of the armature surfaces of the movable contact and the stationary contact is a spherical armature surface having a recess at the center. The release-type electromagnetic solenoid according to claim 1, wherein the permanent magnet is a ring-shaped permanent magnet and is magnetized in the axial direction of the ring. 2. The release electromagnetic solenoid according to claim 1, wherein the permanent magnet is a ring-shaped permanent magnet and is magnetized in a radial direction of the ring. A through hole into which the movable contact is inserted is formed in the yoke, and a movable contact guide made of a non-magnetic material is provided between the through hole and the movable contact. A release-type electromagnetic solenoid according to 1. The release electromagnetic solenoid according to claim 4, wherein the movable contact guide is formed integrally with a winding frame. 2. The release electromagnetic solenoid according to claim 1, wherein a magnet support guide made of a non-magnetic material is provided in a hollow portion of the permanent magnet. 7. The release electromagnetic solenoid according to claim 6, wherein the magnet support guide is formed integrally with the winding frame. The release type electromagnetic solenoid according to any one of claims 1 to 7, wherein the movable contact has a stepped structure in which a shaft diameter of a rear end side shaft portion is smaller than that of a tip of the movable contact.

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