ELECTROMAGNETIC CONTACTOR

Abstract

An electromagnetic shield comprises: a box-shaped arc-quenching wall, arranged in an enclosure, and containing a pair of fixed contacts and a movable contact; a first and a second arc-quenching chamber provided on one side and the other side of the movable contact along its longitudinal axis, the first and second arc-quenching chambers being spaces enclosed by the arc-quenching wall; a pair of arc-quenching permanent magnets arranged to face each other and configured to extend a first arc generated between the first fixed contact point and the first movable contact point in the first arc-quenching chamber; a first opening provided in a wall section of the arc-quenching wall, the wall section being on the side toward which the first arc is extended;and a second opening provided in a wall section of the arc quenching wall, the wall section being located on a side to which the second arc is extended;

Description

Technical area

[0001] The present invention relates to an electromagnetic contactor for opening and closing a current path. background

[0002] For example, an electromagnetic contactor in PATENT DOCUMENT 1 includes a pair of fixed contacts each having a fixed contact point, a movable contact having a pair of movable contact points capable of coming into contact with and separating from the fixed contact points of the pair of fixed contacts, a contact point case in which the pair of fixed contacts and the movable contact are installed, an electromagnet unit connected to the movable contact via a drive shaft, and an arc-extinguishing permanent magnet configured to prolong an arc generated between the fixed contact point and the movable contact point in the contact point case.

[0003] In the electromagnetic contactor in PATENT 1, when arcs are generated between the pair of fixed contact points and the pair of movable contact points at the time when the current path is interrupted, the magnetic flux of the arc-extinguishing permanent magnets crosses the arcs, so that the arcs, to which Lorentz forces are applied due to Fleming's left-hand rule, are prolonged and extinguished within the contact point case. List of citationsPatent literature

[0004] PATENT DOCUMENT 1: JP 5629106 B2 Brief description of the inventionTechnical problem

[0005] However, in the electromagnetic contactor in Patent Document 1, when an arc is generated at the time the high current is turned off, the fixed contact point and the movable contact point melt, leaving a large amount of metal vapor in the contact point housing. The pressure of the metal vapor may increase locally, causing airflow of the metal vapor to act in a direction that reverses the direction in which the arc is extended, which may reduce the arc extinguishing performance.

[0006] In view of the above, an object of the present invention is to provide an electromagnetic contactor that can prevent arc extinguishing performance from decreasing even when much metal vapor is generated at the time of turning off a high current. Solution to the problem

[0007] To achieve the above object, an electromagnetic contactor according to one aspect of the invention comprises: a pair of fixed contacts having first and second fixed contact points; a movable contact having first and second movable contact points at opposite ends in a longitudinal direction of the movable contact, the first and second movable contact points being capable of contacting and separating from the first and second fixed contact points; an electromagnet unit configured to drive the movable contact; a housing configured to accommodate the pair of fixed contacts, the movable contact, and the electromagnet unit; a box-shaped arc-extinguishing wall having a first opening and a second opening and arranged in the housing such thatthat it includes the pair of fixed contacts and the movable contact; and a pair of arc-extinguishing permanent magnets arranged to face each other and configured to extend a first arc generated between the first fixed contact point and the first movable contact point toward a first arc-extinguishing space, and to extend a second arc generated between the second fixed contact point and the second movable contact point toward a second arc-extinguishing space. The first arc-extinguishing space and the second arc-extinguishing space are formed on one side and the other side of the movable contact in the longitudinal direction to be surrounded by the arc-extinguishing wall. The first opening is formed in a wall portion located on one side of the arc-extinguishing wall to which the first arc is extended.and the second opening is formed in a wall portion located on a side of the arc extinguishing wall to which the second arc is extended. Advantageous effects of the invention

[0008] With the electromagnetic contactor according to the present invention, it is possible to prevent a reduction in arc extinguishing performance even if much metal vapor is generated at the time when high current is turned off. Short description of drawings FIG. Fig. 1 is a cross-sectional view of an electromagnetic contactor according to a first embodiment of the present invention. Fig. 2 is a perspective view illustrating the shape of an arc extinguishing wall constituting the electromagnetic contactor. Fig. 3 is a perspective view illustrating a pair of arc-extinguishing permanent magnets and a pair of magnetic pole plates attached to the arc-extinguishing wall. Fig. 4 is an arrow view along the line AA in Fig. 1. Fig. 5 is a cross-sectional view of an electromagnetic contactor according to a second embodiment of the present invention. Description of embodiments

[0009] Embodiments of the present invention will be described below with reference to the drawings. In the drawings to which reference will be made in the following description, identical or similar portions have identical or similar reference numerals. Note that the drawings are schematic, and a relationship between thickness and flat dimensions, a ratio between layer thicknesses, and the like differ from actual ones. Accordingly, a specific thickness or dimension should be determined in light of the following description. It is further understood that the drawings include portions having a different dimensional relationship or ratio.

[0010] Each embodiment describes a device or method for embodying the technical idea of ​​the present invention, and the technical idea of ​​the present invention does not specify the quality, shape, structure, arrangement, and the like of components other than those described below. Various modifications may be made to the technical idea of ​​the present invention within a technical scope defined by the claims described in the claims.

[0011] Note that terms indicating directions such as "upward," "downward," "left," and "right" described in the following description are used by reference to directions in the accompanying drawings. [First embodiment]

[0012] Fig. 1 illustrates an electromagnetic contactor 1 according to a first embodiment of the present invention.

[0013] The electromagnetic contactor 1 is an encapsulated high-voltage contactor for opening and closing a main circuit using electromagnetic force. It includes an airtight container 2 made of resin and having electrically insulating properties, and a pair of fixed contacts 3, a movable contact 4, and an electromagnet unit 5 installed in the airtight container 2. The electromagnet unit 5 drives the movable contact 4 in a direction along which the movable contact 4 comes into contact with and separates from the pair of fixed contacts 3.

[0014] The airtight container 2 consists of a case 6 and a cover 7, and an arc-extinguishing gas is enclosed within the airtight container 2. Note that a housing according to the present invention corresponds to the airtight container 2.

[0015] The case 6 is a square tubular element that has an open lower end (one end) and a closed upper end (the other end) in Fig. 1. The cover 7 is a cover-shaped member. Respective open ends of the lower end of the case 6 and the cover 7 fit together to be bonded by adhesive.

[0016] The pair of fixed contacts 3a and 3b are electrodes made of metal having conductivity and formed in a generally cylindrical shape. The pair of fixed contacts 3a, 3b are integrated by injection molding so as to penetrate through a wall portion of the case 6. Threaded holes 8 are formed in the upper portions of the pair of fixed contacts 3a, 3b and exposed outside the case 6. Clamping screws (not illustrated) on a primary side and a secondary side of the main circuit engage the threaded holes 8. Respective lower portions of the pair of fixed contacts 3a and 3b protrude into the interior of the case 6, and fixed contact pads 9a and 9b are formed in the lower portions. Note that first and second fixed contact pads according to the present invention correspond to the fixed contact pads 9a and 9b.

[0017] The movable contact 4 is made of metal having conductivity and formed in a flat plate shape extending in the direction from right to left in Fig. 1 such that the movable contact 4 is configured to face the pair of fixed contacts 3. A pair of movable contact points 10a and 10b configured to come into contact with and separate from the fixed contact point 9a, 9b of the pair of fixed contacts 3a and 3b are formed in opposite ends of the movable contact 4 in the right-to-left direction.

[0018] The movable contact 4 is connected to the electromagnet unit 5 via a contact point support 11. The contact point support 11 includes a base 12 connected to the electromagnet unit 5, a pressing member 13 configured to hold the movable contact 4, and a contact spring 14 configured to apply contact pressure to the movable contact 4. The contact spring 14 is a compression coil spring and is provided between the base 12 and the movable contact 4 to press the movable contact 4 upward into Fig. 1. When the contact spring 14 elastically supports the movable contact 4 as such, the contact pressure between the movable contact point 10a and 10b and the fixed contact point 9a and 9b is kept constant.

[0019] The electromagnet unit 5 includes a roller 20, a sliding collar 21, a movable piston 22, an armature 23, a pair of outer yokes 24a and 24b, a pair of lower yokes 25a and 25b, a piston ring 26, a return spring 27, a permanent magnet 28 and an auxiliary yoke 29.

[0020] The reel 20 is a winding frame made of a resin having electrically insulating properties, and a coil 31 is wound around a winding spindle 30 having a cylindrical shape and extending in an up-down direction.

[0021] The sliding collar 21 is formed in a cylindrical shape by using resin having electrically insulating properties, and is inserted into the winding spindle 30 from below in the up-down direction such that the sliding collar 21 fits into the winding spindle 30.

[0022] The movable piston 22 is formed in a columnar shape extending in the up-down direction as a moving core and fits into the sliding collar 21 such that the movable piston 22 is guided to advance or retract along its axial direction. An upper portion of the movable piston 22 in the up-down direction is connected to the base 12 of the contact point support 11 via a coupler 32. The armature 23 is a disc-shaped yoke and is fixed to a lower end portion of the movable piston 22.

[0023] The pair of outer yokes 24 are plate-shaped yokes and are fixed to the left and right sides of the winding spindle 30. The pair of lower yokes 25a and 25b are fixed to respective lower portions of the pair of outer yokes 24a and 24b such that the pair of lower yokes 25a and 25b extend to the left and right sides on the same extension line.

[0024] The piston ring 26 is a cylindrical yoke extending in the up-down direction and inserted into the winding spindle 30 from above in the up-down direction to fit therein such that the piston ring 26 is fixed to upper parts in respective upper portions of the pair of outer yokes 24 in the up-down direction. The piston ring 26 has an inner diameter larger than the outer diameter of the movable piston 22 and is adjusted to maintain a predetermined distance relative to the movable piston 22.

[0025] The return spring 27 is a compression coil spring. The return spring 27 is passed through the movable piston 22 in a state where the return spring 27 is sandwiched between the armature 23 and the sliding collar 21, and biases the movable piston 22 downward in the up-down direction relative to the spool 20.

[0026] The permanent magnet 28 has a rectangular flat plate shape with a round hole. The permanent magnet 28 is configured to make contact with respective lower portions of the pair of lower yokes 25a, 25b and surround the armature 23. The auxiliary yoke 29 is a flat-shaped yoke and is attached to the lower portion of the permanent magnet 28.

[0027] The electromagnetic contactor of the present embodiment further includes an arc-extinguishing wall 35 configured to surround the pair of fixed contacts 3a and 3b and the movable contact 4. Furthermore, a pair of arc-extinguishing permanent magnets 36 and 37 and a pair of magnetic pole plates 38 and 39 are mounted on the arc-extinguishing wall 35.

[0028] As in Fig. As illustrated in Figure 2, the arc-extinguishing wall 35 is a box-shaped body made of ceramics or synthetic resin. The arc-extinguishing wall 35 includes a rectangular plate-shaped cover 35a having a pair of contact holes 35a1 through which the pair of fixed contacts 3a and 3b are passed, short-side walls 35b and 35c and long-side walls 35d and 35e extending in the same direction from four edge portions of the cover 35a, and support plates 35f extending outward at right angles from each of the short-side walls 35b and 35c and the long-side walls 35d and 35e. At the interfaces between a short-side wall and a long-side wall that are adjacent to each other (e.g.,In the case where the short-side wall 35b and the long-side wall 35e are adjacent to each other, no corner portion is provided, and four openings 40a to 40d are formed to extend linearly in the same direction as a direction in which the short-side walls 35b, 35c and the long-side walls 35d and 35e extend. Note that a first opening in the present invention corresponds to the corner openings 40a and 40b, and a second opening in the present invention corresponds to the corner openings 40c and 40d.

[0029] As in Fig. 3, the pair of arc-extinguishing permanent magnets 36 and 37 are arranged on the support plate 35f to strike the short-side walls 35b and 35c of the arc-extinguishing wall 35.

[0030] As in Fig. 3, the magnetic pole plate 38 is on one side a member including a magnetic stop plate 38a and a pair of parallel plate portions 38d and 38e extending parallel to each other via bent portions 38b and 38c from the left and right sides of the magnetic stop plate 38a. As shown in Fig. 3, the magnetic pole plate 38 is arranged on the supporting surfaces 35f with the magnetic stop plate 38a abutting the arc-extinguishing permanent magnet 36 and with the pair of parallel plate portions 38d and 38e abutting the long-side walls 30d and 35e of the arc-extinguishing wall 35. The bent portions 38b and 38c of the magnetic pole plate 38 face the openings 40 of the arc-extinguishing wall 35 such that external communication spaces 41a and 41b are formed outside the two corner openings 40a and 40b. As further shown in Fig. 3, the magnetic pole plate 39 on the other side is also a member including a magnetic stopper plate 39a and a pair of parallel plate portions 39d and 39e extending parallel to each other via bent portions 39b and 39c from the right and left sides of the magnetic stopper plate 39a. The magnetic pole plate 39 is also arranged on the support plates 35f, with the magnetic stopper plate 39a abutting the arc-extinguishing permanent magnet 37 disposed on the short-side wall 35c side of the arc-extinguishing wall 35, and with the pair of parallel plate portions 39d and 39e abutting the long-side walls 35d and 35e of the arc-extinguishing wall 35. The bent portions 39b and 39c of the magnetic pole plate 39 face the openings 40 of the arc extinguishing wall 35 such that two outer communication spaces 41c and 41d are formed outside the two corner openings 40c and 40d.Note that a first external communication space according to the present invention corresponds to the external communication spaces 41a and 41b, and a second external communication space according to the present invention corresponds to the external communication spaces 41c and 41d.

[0031] As in Fig. 4, the arc-extinguishing wall 35 on which the pair of arc-extinguishing permanent magnets 36 and 37 and the pair of magnetic pole plates 38 and 39 are integrally arranged is attached to the inner wall of the case 6 in a state where the arc-extinguishing wall 35 surrounds the pair of fixed contacts 3a and 3b and the movable contact 4.

[0032] A pole face of the arc-extinguishing permanent magnet 36 that abuts the short-side wall 35b is the S pole, and a pole face of the arc-extinguishing permanent magnet 37 that abuts the short-side wall 35c is the N pole.

[0033] The fixed contact point 9a of the fixed contact 3a on one side and the movable contact point 10a of the movable contact 4, where the movable contact point 10 comes into contact with and separates from the fixed contact point 9a, are referred to as a contact section 42a. The contact point 9b of the fixed contact 3b on the other side and the movable contact point 10b of the movable contact 4, where the movable contact point 10b comes into contact with and separates from the fixed contact point 9b, are referred to as a contact section 42b. In this case, the magnetic flux (dotted arrows in Fig. 4) flowing from the arc-extinguishing permanent magnet 37 on one side to the arc-extinguishing permanent magnet 36 on the other side, the contact portions 42a and 42b.

[0034] A room separated from the arc extinguishing wall 35 on the left side in Fig. 4 relative to the contact section 42a is referred to as a first arc extinguishing space S1. A space enclosed by the arc extinguishing wall 35 on the left side in Fig. 4 relative to the contact portion 42b is referred to as a second arc-extinguishing space S2. The first arc-extinguishing space S1 and the second arc-extinguishing space S2 communicate with four external communication spaces 41a to 41d formed by the pair of magnetic pole plates 38 and 39 via four corner openings 40a to 40d formed in the arc-extinguishing wall 35. The four external communication spaces 41a to 41d communicate with a space in which the electromagnet unit 5 is installed in the airtight container 2 (the case 6).

[0035] Next, the operation of the electromagnetic contactor 1 of the present embodiment will be described with reference to Fig. 4 described.

[0036] The electromagnetic contactor 1 of the present embodiment includes a positive terminal (+) connected to the fixed contact 3a on one side and a negative terminal (-) connected to the fixed contact 3b on the other side.

[0037] Here, assume a case where the coil 31 of the electromagnet unit 5 is in a de-energized state and in a released state in which the electromagnet unit 5 does not generate exciting force to move the movable piston 22 upward. In this released state, the movable piston 22 is biased downward by the return spring 27, and the armature 23 adheres to the auxiliary yoke 29 due to the action of the permanent magnet 28. Accordingly, the movable contact 4 connected to the movable piston 22 is spaced downward from the pair of fixed contacts 3a and 3b only by a predetermined distance. Accordingly, the current path between the pair of fixed contacts 3a and 3b is interrupted, and the contact portions 42a and 42b are opened (an open state of the contact portions 42a, 42b).

[0038] When a current is applied to the coil 31 of the electromagnet unit 5 from the open state of the contact portions 42a and 42b, exciting force is generated in the electromagnet unit 5 to push the movable piston 22 upward against the attractive force from the permanent magnet 28 to the auxiliary yoke 29 and biasing force from the return spring 27 such that the armature 23 adheres to the lower yokes 25a, 25b.

[0039] When the movable piston 22 as such moves upward, the movable contact 4 connected to the movable piston 22 also moves upward, and the movable contact points 10a, 10b of the movable contact 4 come into contact with the fixed contact points 9a and 9b of the pair of fixed contacts 3a, 3b due to the contact pressure from the contact spring 14 so that the contact portions 42a, 42b are closed.

[0040] When a high-current flow into the main circuit from the closed state of the contact portions 42a and 42b and the current application to the coil 31 of the electromagnet unit 5 is interrupted, no exciting force is generated to move the movable piston 22 upward in the electromagnet unit 5, so the movable piston 22 moves downward due to the biasing force of the return spring 27, and the armature 23 adheres to the auxiliary yoke 29 due to the action of the permanent magnet 28. When the movable piston 22 moves downward, the movable contact 4 connected to the movable piston 22 separates downward from the pair of fixed contacts 3a and 3b to enter an opening start state.

[0041] When a high current flows into the main circuit to bring the contact portions 42a and 42b into the opening start state, a first arc is formed in the contact portion 42a, and a second arc is formed in the contact portion 42b, so that a current application state is continued due to the first and second arcs. The current direction of the first arc is a direction from the fixed contact point 9a toward the movable contact point 10a, and the current direction of the second arc is a direction from the movable contact point 10b to the fixed contact point 9b.

[0042] At this time, the magnetic flux flowing from the N pole of the arc-extinguishing permanent magnet 37 to the S pole of the arc-extinguishing permanent magnet 36 crosses the first arc and the second arc. From the relationship between the current flow of the first arc and the magnetic flux, a Lorentz force F1 is generated toward the corner opening 40a of the arc-extinguishing wall 35 on the upper left side of the first arc-extinguishing space S1 in Fig. 4 is generated due to Fleming's left-hand rule. From the relationship between the current flow of the second arc and the magnetic flux, a Lorentz force F2 is generated in the direction of the corner opening 40d of the arc extinguishing wall 35 at the upper left side of the second arc extinguishing chamber S2 in Fig. 4 is generated based on Fleming's left-hand rule.

[0043] When the Lorentz force F1 is generated, the first arc is widely directed toward the corner opening 40a of the arc extinguishing wall 35 at the upper left side of the first arc extinguishing space S1 in Fig. 4 and cooled by contact with arc-extinguishing gas. The thus-extended first arc is then cooled by contact with the bent portion 38b of the magnetic pole plate 38, which forms the outer communication space 41a, through the corner opening 40a. When the Lorentz force F2 is generated, the second arc is widely extended toward the corner opening 40d of the arc-extinguishing wall 35 on the upper left side of the second arc-extinguishing space S2 in Fig. 4 and cooled by contact with arc-extinguishing gas. The second arc thus extended is then cooled by contact with the bent portion 39c of the magnetic pole plate 39, which forms the outer communication space 41d, through the corner opening 40d.

[0044] When a high current flows into the main circuit to open the contact portions 42a, 42b, the fixed contact point 9a and the movable contact point 10a in the contact portion 42a melt due to a temperature rise in the first arc, generating a large amount of high-temperature metal vapor. Furthermore, the fixed contact point 9b and the movable contact point 10b in the contact portion 42b also melt due to a temperature rise in the second arc, generating a large amount of high-temperature metal vapor.

[0045] The metal vapor generated in the contact section 42a flows into the first arc extinguishing space S1. As shown in Fig. As illustrated in Figure 4, the metal vapor passes through the external communication spaces 41a and 41b from the corner openings 40a and 40b of the arc-extinguishing wall 35 and flows to the space where the electromagnet unit 5 is installed. Further, the metal vapor generated in the contact portion 42b flows into the second arc-extinguishing space S2, and then the metal vapor passes through the external communication spaces 41c and 41d from the corner openings 40c and 40d of the arc-extinguishing wall 35 and flows to the space where the electromagnet unit 5 is installed. The metal vapor flowing through the outer communication spaces 41a to 41d is cooled by contact with the bent portions 38b and 38c and the bent portions 39b and 39c of the magnetic pole plates 38 and 39, the bent portions 38b and 38c and the bent portions 39b and 39c forming the outer communication spaces 41a to 41d.

[0046] Next, the operation / working effects of the electromagnetic contactor 1 of the present disclosure will be described.

[0047] When the first arc is generated in the contact portion 42a at the time of turning off the high current, the Lorentz force F1 is generated toward the corner opening 40a of the arc-extinguishing wall in the first arc-extinguishing space S1 due to the relationship between the current flow of the first arc and the magnetic flux, so that the first arc can be widely extended. Further, when the second arc is generated in the contact portion 42b, the Lorentz force F2 is generated toward the corner opening 40d of the arc-extinguishing wall 35 in the second arc-extinguishing space S2 due to the relationship between the current flow of the second arc and the magnetic flux, so that the second arc can also be widely extended.

[0048] Even if a large amount of high-temperature metal vapor is generated in the contact portions 42a and 42b at the time of turning off the high current, the metal vapor generated in the contact portion 42a flows toward the external communication spaces 41a and 41b via the corner openings 40a and 40b of the arc-extinguishing wall 35, and then flows toward the space where the electromagnet unit 5 is installed. Furthermore, the metal vapor generated in the contact portion 42b also flows toward the external communication spaces 41c and 41d via the corner openings 40c and 40d of the arc-extinguishing wall 35, and then flows toward the space where the electromagnet unit 5 is installed. Therefore, the metal vapor generated in the contact portions 42a and 42b does not remain in the first arc extinguishing space S1 and the second arc extinguishing space S2, and no pressure increase occurs.Since the metal vapor causes air flows to directions toward the corner openings 40a and 40d of the arc extinguishing wall 35, the first arc and the second arc are further extended.

[0049] Accordingly, the first arc and the second arc are effectively extended along the air streams of the metal vapor so that the breaking performance can be improved.

[0050] Furthermore, the widely extended first arc is cooled by contact with the bent portion 38b of the magnetic pole plate 38 forming the external communication space 41a through the corner opening 40a, and the second arc thus widely extended is further cooled by contact with the bent portion 39c of the magnetic pole plate 39 forming the external communication space 41d through the corner opening 40d, so that the breaking performance can be further improved.

[0051] Furthermore, the metal vapor flowing to the outer communication spaces 41a and 41b from the corner openings 40a and 40b of the arc opening 30 and the metal vapor flowing to the outer communication spaces 41c and 41d from the corner openings 40c and 40d of the arc extinguishing wall 35 are efficiently cooled by contact with the bent portions 38b and 38c and the bent portions 39b and 39c of the magnetic pole plates 38 and 39, the bent portions 38b and 38c and the bent portions 39b and 39c constituting the outer communication spaces 41a to 41d such that the phase of the metal vapor changes to liquid or to solid. As a result, the pressure and temperature in the airtight container 2 decrease in a short time, so that it is possible to prevent a reduction in the arc extinguishing performance and to prevent the first arc and the second arc from being regenerated. [Second embodiment]

[0052] Fig. 5 illustrates an essential portion of the electromagnetic contactor 1 according to a second embodiment of the present invention. In the present embodiment, the electromagnetic contactor 1 includes a pair of arc-extinguishing permanent magnets 45 and 46, which have a configuration different from that of the pair of arc-extinguishing permanent magnets 36 and 37 in the first embodiment. The other configurations are the same as those of the first embodiment and are referred to by the same reference numerals as those used in the first embodiment, and are not described herein.

[0053] In the present embodiment, a pole face of the arc-extinguishing permanent magnet 45 on one side, which pole face abuts the short-side wall 35b, is the N pole, and a pole face of the arc-extinguishing permanent magnet 46 on the other side, which pole face abuts the short-side wall 35c, is the N pole.

[0054] As in broken lines in Fig. 5, the arc-extinguishing permanent magnet 45 on one side generates the magnetic flux flowing from the short-side wall 35b of the arc-extinguishing wall 35 to the long-side walls 35d and 35, and the arc-extinguishing permanent magnet 46 on the other side generates magnetic flux flowing from the short-side wall 35c of the arc-extinguishing wall 35 to the long-side walls 35d, 35e.

[0055] In the electromagnetic contactor 1 of the present embodiment, when a high current flows into the main circuit to bring the contact portions 42a and 42b into the opening start state, the first arc is generated in the contact portion 42a, and the second arc is generated in the contact portion 42b, so that the current application state continues due to the first arc and the second arc. The current direction of the first arc is a direction from the fixed contact point 9a toward the movable contact point 10a, and the current direction of the second arc is a direction from the movable contact point 10b to the fixed contact point 9b.

[0056] At this time, from the relationship between the current flow of the first arc and the magnetic flux of the arc-extinguishing permanent magnet 45 on one side, a Lorentz force F1 is generated toward the corner opening 40b of the arc-extinguishing wall 35 on the lower left side in the first arc-extinguishing space S1 due to Fleming's left-hand rule. Further, from the relationship between the current flow of the second arc and the magnetic flux of the arc-extinguishing permanent magnet 46 on the other side, a Lorentz force F2 is generated toward the corner opening 40d of the arc-extinguishing wall 35 on the lower right side of the second arc-extinguishing space S2 due to Fleming's left-hand rule.

[0057] When the Lorentz force F1 is generated, the first arc is extended far toward the corner opening 40b of the arc-extinguishing wall 35 at the lower left side of the first arc-extinguishing space S1 and cooled by contact with arc-extinguishing gas. The thus-extended first arc is then cooled by contact with the bent portion 38c of the magnetic pole plate 38 forming the external communication space 41b through the corner opening 40a. Further, when the Lorentz force F2 is generated, the second arc is extended far toward the corner opening 40d of the arc-extinguishing wall 35 at the upper left side of the second arc-extinguishing space S2 and cooled by contact with arc-extinguishing gas. The thus-extended second arc is then cooled by contact with the bent portion 39c of the magnetic pole plate 39 forming the external communication space 41d through the corner opening 40d.

[0058] Further, metal vapor generated in the contact portion 42a flows to the first arc-extinguishing space S1, and the metal vapor passes through the external communication spaces 41a and 41b from the corner openings 40a, 40b of the arc-extinguishing wall 35 and flows to the space where the electromagnet unit 5 is installed. Further, metal vapor generated in the contact portion 42b flows into the second arc-extinguishing space S2, and the metal vapor then passes through the external communication spaces 41c and 41d from the corner openings 40c and 40d of the arc-extinguishing wall 35 and flows to the space where the electromagnet unit 5 is installed.The metal vapor flowing through the outer communication spaces 41a to 41d is cooled by contact with the bent portions 38b and 38c and the bent portions 39b and 39c of the magnetic pole plates 38 and 39, the bent portions 38b and 38c and the bent portions 39b and 39c forming the outer communication spaces 41a to 41d.

[0059] In the electromagnetic contactor 1, when the first arc is generated in the contact portion 42a at the time of turning off the high current, the Lorentz force F1 is generated toward the corner opening 40b of the arc-extinguishing wall 35 in the first arc-extinguishing space S1 due to the relationship between the current flow of the first arc and the magnetic flux of the arc-extinguishing permanent magnet 45 on the other side, so that the first arc can be widely extended. Further, when the second arc is generated in the contact portion 42b, the Lorentz force F2 is generated toward the corner opening 40d of the arc-extinguishing wall 35 in the second arc-extinguishing space S2 due to the relationship between the current flow of the second arc and the magnetic flux, so that the second arc can also be widely extended.

[0060] Even if a large amount of high-temperature metal vapor is generated in the contact portions 42a and 42b at the time of cutting off the high current, the metal vapor generated in the contact portion 42a flows toward the external communication spaces 41a and 41b via the corner openings 40a and 40b of the arc-extinguishing wall 35 and then flows toward the space where the electromagnet unit 5 is installed. Furthermore, the metal vapor generated in the contact portion 42b also flows toward the external communication spaces 41c and 41d via the corner openings 40c and 40d of the arc-extinguishing wall 35 and then flows toward the space where the electromagnet unit 5 is installed. Therefore, the first arc and the second arc are effectively extended along the air currents of the metal vapor, so that the cutting performance can be improved.

[0061] Similar to the first embodiment, the first arc is further cooled by contact with the bent portion 38c of the magnetic pole plate 38, and the second arc is also further cooled by contact with the bent portion 39c of the magnetic pole plate 39, so that the breaking performance can be further improved.

[0062] Further, similarly to the first embodiment, the metal vapor comes into contact with the bent portions 38b and 38c and the bent portions 39b and 39c of the magnetic pole plates 38 and 39, the bent portions 38b and 38c and the bent portions 39b and 39c forming the external communication spaces 41a to 41d, so that it is possible to prevent a reduction in the arc extinguishing performance and to prevent the first arc and the second arc from being regenerated. List of reference symbols 1 electromagnetic contactor 2 airtight containers 3a, 3b fixed contact 4 movable contact 5 Electromagnet unit 6 cases 7 Cover 8 threaded holes 9a, 9b fixed contact point 10a, 10b movable contact point 11 contact point holders 12 Base 13 Press element 14 Contact spring 20 rolls 21 Sliding collar 22 movable piston 23 anchors 24a, 24b outer yoke 25a, 25b lower yoke 26 piston ring 27 Return spring 28 permanent magnet 29 Auxiliary yoke 30 winding spindle 31 coil 32 couplers 35 Arc extinguishing wall 35a cover 35a1 contact hole 35b, 35c short-sided wall 35d, 35e long side wall 35f support plate 36, 37, 45, 46 Arc extinguishing permanent magnet 38, 39 magnetic pole plate 38a, 39a Magnetic stop plate 38b, 38c, 39b, 39c curved section 38d, 38e, 39d, 39e parallel plate section 40a to 40d corner opening 41a to 41d outer communication space 42a, 42b contact section F1, F2 Lorentz force S1 first arc extinguishing room S2 Second arc extinguishing room QUOTES CONTAINED IN THE DESCRIPTION

[0000] This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions. Cited patent literature

[0000] JP 5629106 B2

[0004]

Claims

[1] Electromagnetic contactor comprising: a pair of fixed contacts having a first and a second fixed contact point; a movable contact having first and second movable contact points at opposite ends in a longitudinal direction of the movable contact, the first and second movable contact points being capable of coming into contact with and separating from the first and second fixed contact points; an electromagnet unit configured to drive the movable contact; a housing configured to accommodate the pair of fixed contacts, the movable contact, and the electromagnet unit; a box-shaped arc-extinguishing wall having a first opening and a second opening and arranged in the housing to contain the pair of fixed contacts and the movable contact; and a pair of arc-extinguishing permanent magnets arranged to face each other and configured to extend a first arc generated between the first fixed contact point and the first movable contact point toward a first arc-extinguishing space, and to extend a second arc generated between the second fixed contact point and the second movable contact point toward a second arc-extinguishing space, wherein the first arc-extinguishing space and the second arc-extinguishing space are formed on one side and the other side of the movable contact in the longitudinal direction such that they are surrounded by the arc-extinguishing wall, wherein the first opening is formed in a wall portion located on a side of the arc extinguishing wall to which the first arc is extended, and a second opening is formed in a wall portion located on a side of the arc extinguishing wall to which the second arc is extended. [2] Electromagnetic contactor according to claim 1, wherein the arc extinguishing wall has a rectangular box shape and the first opening and the second opening are formed at corner portions of the arc extinguishing wall. [3] The electromagnetic contactor according to claim 1 or 2, wherein a first external communication space communicating with the first arc extinguishing space via the first opening and a second external communication space communicating with the second arc extinguishing space via the second opening are formed outside the arc extinguishing wall. [4] An electromagnetic contactor according to claim 3, wherein the first external communication space and the second external communication space are formed by magnetic pole plates arranged to surround the arc extinguishing wall from the outside. [5] An electromagnetic contactor according to claim 3 or 4, wherein the first external communication space and the second external communication space are formed to operatively communicate with an interior space of the housing containing the electromagnet unit. [6] An electromagnetic contactor according to any preceding claim, wherein arc quenching gas is encapsulated in the housing.

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