Sealed electromagnetic contactor

Abstract

To provide a sealed electromagnetic contactor capable of preventing arc-extinguishing gas from leaking to the outside even if a sealed container is bent due to an increase in internal pressure when an arc is generated.SOLUTION: The sealed container is composed of a first member 13 and a second member 12, and is a synthetic resin container in which an arc extinguishing gas is sealed. In the first member, a connecting projection 50 is continuously formed on the whole periphery of the end face of the side wall, and in the second member, a connecting recess 40 into which the connecting projection can be inserted is continuously formed at a position facing the end face of the side wall. The connection recessed line includes an annular inner wall part 41, an annular outer wall part 42 set to have the same thickness as the inner wall part and provided outside the inner wall part, and an annular bottom wall 43 connected to base parts of the inner wall part and the outer wall part. The first member and the second member are integrated by inserting the connection projection into the connection recess and interposing a connection member 60 between an inner wall part, an outer wall part and a bottom wall of the connection recess and the connection projection facing them.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present invention relates to a sealed electromagnetic contactor in which a fixed contact and a movable contact are arranged in a sealed container filled with an arc-extinguishing gas. [Background technology]

[0002] For example, the device disclosed in Patent Document 1 is known as a sealed electromagnetic contactor.

[0003] The sealed electromagnetic contactor of Patent Document 1 contains a pair of fixed contacts with fixed contacts, a movable contactor with a pair of movable contacts that can be brought into contact with and separated from the fixed contacts of the pair of fixed contacts, and an electromagnet that drives the movable contactor, in a sealed container made of synthetic resin. The sealed container is composed of an insulating box and an insulating plate, the insulating box is surrounded on its entire periphery by a side wall and has connecting ridges formed continuously around the entire periphery on the end surfaces of the side wall, the insulating plate is formed with connecting grooves that fit into the connecting ridges, and the insulating box and insulating plate are integrated by inserting the connecting ridges into the connecting grooves via an adhesive.

[0004] The sealed container is filled with arc-extinguishing gas, and an arc is generated when the moving contact of the moving contactor separates from the fixed contact of the fixed contactor by driving the electromagnet, but the arc is cooled and extinguished by the arc-extinguishing gas sealed in the sealed container. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Patent No. 7435487 Summary of the Invention [Problem to be solved by the invention]

[0006] However, in the sealed electromagnetic contactor of Patent Document 1, if the arc-extinguishing space is reduced in accordance with market demands for miniaturization, the internal pressure rises when an arc occurs, causing the sealed container to bend, and localized stress acts on the adhesive interposed between the connecting grooves and connecting ridges, which may cause damage such as cracks. If damage occurs to part of the adhesive in this way, there is a risk that the arc-extinguishing gas sealed in the sealed container will leak to the outside.

[0007] Therefore, the present invention has been made in consideration of the above circumstances, and aims to provide a sealed electromagnetic contactor that can prevent arc-extinguishing gas from leaking to the outside even if the sealed container becomes deflected due to an increase in internal pressure when an arc occurs. [Means for solving the problem]

[0008] In order to achieve the above object, a sealed electromagnetic contactor according to one aspect of the present invention comprises a pair of fixed contacts having fixed contacts, a movable contactor having a pair of movable contacts that can be brought into contact with and separated from the fixed contacts of the pair of fixed contacts, an electromagnet unit that drives the movable contactor, and a sealed container that hermetically houses the pair of fixed contacts and the movable contactor, the sealed container being made of a synthetic resin and made of a first member and a second member and filled with an arc-extinguishing gas, the first member being surrounded by a side wall on the entire periphery and having a connecting ridge formed continuously on the end surface of the side wall. The second member has a series of connecting grooves formed at positions facing the end faces of the side walls, into which the connecting protrusions can be inserted, and the connecting grooves have an annular inner wall portion, an annular outer wall portion set to the same thickness as the inner wall portion and provided on the outside of the inner wall portion, and an annular bottom wall connecting to the inner wall portion and the base of the outer wall portion, and the first member and the second member are integrated by inserting the connecting grooves into them and interposing connecting members between the inner wall portion, outer wall portion and bottom wall of the connecting grooves and the connecting protrusions facing them. [Effects of the Invention]

[0009] According to the sealed electromagnetic contactor of the present invention, even if the sealed container is deflected due to an increase in internal pressure when an arc occurs, leakage of arc-extinguishing gas to the outside can be prevented. [Brief explanation of the drawings]

[0010] [Figure 1] 1 is a perspective view showing the appearance of a sealed electromagnetic contactor according to an embodiment of the present invention; [Figure 2] 1 is a diagram showing a cross section of a sealed container constituting a sealed electromagnetic contactor according to an embodiment; [Figure 3] 10 is a diagram showing connecting grooves formed on a case constituting the sealed container of one embodiment and connecting ridges formed on a cover 13. FIG. [Figure 4] FIG. 10 is a diagram showing a state in which a connecting groove formed on the case and a connecting ridge formed on the cover 13 are integrated via a connecting member. DETAILED DESCRIPTION OF THE INVENTION

[0011] Next, an embodiment of the present invention will be described with reference to the drawings. In the following description of the drawings, identical or similar parts are designated by identical or similar reference numerals. However, it should be noted that the drawings are schematic, and the relationship between thickness and planar dimensions, the thickness ratio of each layer, etc., may differ from the actual ones. Therefore, specific thicknesses and dimensions should be determined with reference to the following description. Furthermore, it goes without saying that the drawings may include parts with different dimensional relationships and ratios. Furthermore, the embodiments shown below are merely examples of devices and methods for embodying the technical concept of the present invention, and the technical concept of the present invention does not limit the materials, shapes, structures, arrangements, etc. of the components to those described below. The technical concept of the present invention can be modified in various ways within the technical scope defined by the claims. In the following description, the three mutually orthogonal directions will be referred to as the vertical direction, the width direction, and the axial direction for convenience.

[0012] FIG. 1 is a diagram showing the appearance of the electromagnetic contactor 11. As shown in FIG. The electromagnetic contactor 11 includes a case 12 and a cover 13 as sealed containers. The case 12 is made of an insulating resin and is formed into a deep container shape with both vertical sides, both width sides, and one axial side closed and the other axial side open. The cover 13 is made of an insulating resin and is formed into a shallow container shape with both vertical sides, both width sides, and the other axial side closed and the other axial side open. One of the first and second members described in the present invention corresponds to the case 12, and the other of the first and second members described in the present invention corresponds to the cover 13. Pressurized arc-extinguishing gas such as nitrogen is sealed inside the case 12 and the cover 13. The open openings of the case 12 and the cover 13 are joined together with an epoxy adhesive. The structure in which the case 12 and the cover 13 are fixed together with the adhesive will be described later.

[0013] In addition, the entire outer surface, including the bonded areas, is gas-barrier coated with a laminated film of clay crystals. Specifically, the interlayer ions of purified smectite are replaced and bound together with an organic binder such as PVA (polyvinyl alcohol) or water-soluble nylon, creating a labyrinth effect that prevents the permeation of gas molecules such as nitrogen. The laminated film is layered in the thickness direction, with a thickness of, for example, 2 μm. The gas-barrier coating is achieved, for example, by spraying a coating liquid into a mist and applying it to the case 12 and cover 13, followed by baking at a temperature of, for example, 150°C or higher, at which the interlayer ions are incorporated into the clay crystals.

[0014] FIG. 2 is a cross-sectional view of the electromagnetic contactor 11 in the released state. The electromagnetic contactor 11 includes a pair of fixed contacts 14 , a movable contact 15 , a contact support 16 , and an electromagnet 17 . The pair of fixed contacts 14 are made of a conductive metal, are formed into a cylindrical shape extending in the axial direction, and are provided on one axial side of the case 12. The pair of fixed contacts 14 are aligned at a distance from each other in the vertical direction, penetrate from the inside to the outside of the case 12, and are integrated with the case 12 by insert molding. The end face of the fixed contact 14 facing the other axial side becomes the fixed contact point.

[0015] The surface of the fixed contact 14 is formed with micron-sized minute irregularities by chemical etching. This allows the molten resin to penetrate the irregularities during insert molding, and as the resin solidifies, the metal and resin are joined at the interface level, forming a complex joint due to the labyrinth effect, preventing leakage of gas molecules such as nitrogen. An example of metal surface treatment technology is "AMALPHA" (registered trademark) by MEC Co., Ltd. Note that the pipe for sealing in the interrupter gas by vacuuming and the pipe for connecting to the electromagnet 17 are also available. The other metal members that are insert-molded into the case 12, such as the coil terminals to be connected, are all subjected to the same surface treatment.

[0016] The movable contactor 15 is made of a conductive metal, extends in the vertical direction, and is formed in the shape of a plate along the vertical and width directions, and is disposed on the other side of the pair of fixed contactors 14 in the axial direction. Both vertical ends of the end face of the movable contactor 15 facing one side in the axial direction become movable contacts facing the fixed contacts. The fixed contact of the fixed contactor 14 and the movable contact of the movable contactor 15 form contact 18, and contact 18 is opened or closed by displacement of the movable contact along the axial direction. The contact support 16 holds the movable contact 15 and a contact spring 19. The contact spring 19 is a compression coil spring that expands and contracts in the axial direction, and biases the movable contact 15 in one axial direction. The electromagnet 17 is disposed on the other side of the contact support 16 in the axial direction, and includes a spool 21, a plunger 22, an outer yoke 23, a bottom yoke 24, a permanent magnet 25, an auxiliary yoke 26, and a back spring 27.

[0017] The spool 21 is made of insulating resin, and has a coil 32 wound around a cylindrical winding shaft 31 extending in the axial direction. A cylindrical sliding collar 34 is fitted inside the winding shaft 31. The plunger 22 is a cylindrical movable iron core extending in the axial direction, and is inserted into a sliding collar 34 in a state in which it can move back and forth in the axial direction. A shaft 35 is fitted into a threaded hole formed in one axial end of the plunger 22, and the shaft 35 is connected to the contact support 16. An armature 36 is connected to the other axial end of the plunger 22. The armature 36 is a disk-shaped yoke that extends in the vertical and width directions.

[0018] The outer yoke 23 is provided to cover both longitudinal sides and one axial side of the spool 21, and is a yoke formed in a generally U-shape that opens toward the other axial side when viewed in the width direction. The tip side of the outer yoke 23 is a pair of side plates extending in the width and axial directions that face each other in the longitudinal direction. A shaft 35 is inserted through a round hole that penetrates in the axial direction in the flat plates of the outer yoke 23 extending in the longitudinal and width directions. The bottom yoke 24 is a flat yoke extending in the vertical and width directions, and is located on the other side of the axial direction from the winding shaft 31 of the spool 21, and is fixed to the other axial end of the outer yoke 23. The plunger 22 is inserted through the bottom yoke 24 via a circular hole that penetrates in the axial direction.

[0019] The permanent magnet 25 is a flat plate extending in the vertical and width directions, has a circular hole passing through in the axial direction, and is attached to the surface of the bottom yoke 24 facing the other axial direction. The auxiliary yoke 26 is a flat plate extending in the vertical and width directions, has a circular hole passing through it in the axial direction, and is attracted to the surface of the permanent magnet 25 facing the other axial direction. The armature 36 is disposed between the bottom yoke 24 and the auxiliary yoke 26. The back spring 27 is a compression coil spring that expands and contracts in the axial direction, and is interposed between the sliding collar 34 and the armature 36, and biases the plunger 22 in the other axial direction via the armature 36.

[0020] Next, the structure in which the case 12 and the cover 13 are integrated with an adhesive will be described in detail with reference to FIGS. 2, the opening of the case 12 that is open on the other axial side has a connecting groove 40 formed continuously around the entire circumference of the opening. Also, the opening of the cover 13 that is open on one axial side has a connecting ridge 50 that can be inserted into the connecting groove 40 formed continuously around the entire circumference of the opening.

[0021] As shown in Figure 3, the connecting groove 40 of the case 12 includes a rectangular annular inner wall 41 that defines the opening of the case 12, a rectangular annular outer wall 42 that extends parallel to the inner wall 41 and vertically and widthwise outward from the inner wall 41, and a bottom wall 43 that extends vertically on one axial side of the base ends of the inner and outer walls 41 and is continuous with the inner and outer walls 41, 42. The thickness T1 of the inner wall 41 and the thickness T2 of the outer wall 42 are set to be the same (T1 = T2). The axial dimension H1 of the inner wall 41 is set to be longer than the axial dimension H2 of the outer wall 42 (H1 > H2).

[0022] As shown in Figure 3, the connecting protrusion 50 of the cover 13 has a first abutment surface 51 that can abut against the outer peripheral surface of the inner wall portion 41 (the surface facing the outer wall portion 42) when inserted into the connecting groove 40, a second abutment surface 52 that can abut against the bottom wall 43, a third abutment surface 53 that can abut against the inner peripheral surface of the outer wall portion 42 (the surface facing the inner wall portion 41), and a fourth abutment surface 54 that extends from the third abutment surface 53 outward in the vertical direction and width direction of the connecting protrusion 50 and can abut against the end surface 42a facing the other axial direction of the outer wall portion 42 of the connecting groove 40.

[0023] 4 shows a state in which the case 12 and the cover 13 are integrated by inserting the connecting ridges 50 of the cover 13 into the connecting grooves 40 of the case 12 with an epoxy adhesive 60 interposed therebetween. The connecting member described in the present invention corresponds to the adhesive 60. Here, the connecting member described in the present invention is not limited to the liquid (epoxy) adhesive 60, but may also be a film-like or plate-like adhesive member.

[0024] The adhesive 60 is applied over the entire area between the fourth abutment surface 54 of the cover 13 and the end surface 42a of the outer wall portion 42 of the connecting groove 40, the entire area between the third abutment surface 53 of the cover 13 and the inner peripheral surface of the outer wall portion 42 of the connecting groove 40, and the entire area between the second abutment surface 52 of the cover 13 and the bottom wall 43 of the connecting groove 40. Here, the adhesive 60 applied between the first abutment surface 51 of the cover 13 and the outer surface of the inner wall portion 41 of the connecting groove 40 does not extend to the tip of the inner wall portion 41, but extends up to a position approximately equal to the axial dimension H2 of the outer wall portion 42. In this way, by inserting the connecting ridges 50 of the cover 13 into the connecting grooves 40 of the case 12 with the adhesive 60 interposed therebetween, the case 12 and the cover 13 are integrated to form an airtight sealed container, and arc-extinguishing gas is sealed inside the sealed container.

[0025] In the electromagnetic contactor 11 configured as described above, when the coil 32 is not energized and is in a non-excited state, the magnetic force of the permanent magnet 25 and the repulsive force of the back spring 27 cause the plunger 22 to be displaced in the other axial direction. The magnetic flux of the permanent magnet 25 passes from one side of the permanent magnet 25 through the bottom yoke 24, outer yoke 23, plunger 22, armature 36, and auxiliary yoke 26 in this order to the other side of the permanent magnet 25. This closed-loop magnetic circuit attracts the armature 36 to one side of the auxiliary yoke 26. Thus, when the plunger 22 is displaced in the other axial direction, the contact 18 opens via the contact support 16, resulting in a released state. At this time, the armature 36 is separated from the bottom yoke 24.

[0026] When the coil 32 is energized and excited, the magnetic force of the coil 32 attracts the armature 36 to the other surface of the bottom yoke 24. As a result, the plunger 22 is displaced to one side in the axial direction against the magnetic force of the permanent magnet 25 and the repulsive force of the back spring 27. The magnetic flux of the coil 32 flows from the plunger 22, through the armature 36 and the bottom yoke 24, and then to the outer yoke 23. This closed-loop magnetic circuit attracts the armature 36 to the other surface of the bottom yoke 24. When the plunger 22 is displaced to one side in the axial direction, the contact 18 closes via the contact support 16, establishing a closed state. At this time, the armature 36 is spaced apart from the auxiliary yoke 26.

[0027] Furthermore, if a large current flows when the contact 18 is in the closed state, an arc occurs between the fixed contact of the fixed contactor 14 and the movable contact of the movable contactor 15, and the arc is cooled and extinguished by the arc-extinguishing gas sealed in the sealed container. When an arc occurs, the internal pressure rises, causing the sealed container (case 12 and cover 13) to expand, and the connecting grooves 40 of the case 12 and the connecting ridges 50 of the cover 13 to bend. At this time, the inner wall 41 and the outer wall 42 of the connecting grooves 40 of the case 12 are set to the same thickness (T1 = T2), so the inner wall 41 and the outer wall 42 bend by approximately the same amount when internal pressure is applied. If the inner wall 41 and the outer wall 42 bend by approximately the same amount, no local stress acts on the adhesive 60 interposed between the connecting ridges 50 and the connecting grooves 40, and damage such as cracks does not occur.

[0028] Furthermore, when the temperatures of the fixed contact 14 and the movable contact 15 rise due to the generation of an arc, the fixed contacts and the movable contacts melt, generating metal vapor. If the adhesive 60 is exposed to this metal vapor, it may be damaged. However, in this embodiment, the adhesive 60 interposed between the first abutment surface 51 of the cover 13 and the outer surface of the inner wall portion 41 of the connection groove 40 does not extend to the tip of the inner wall portion 41, so the adhesive 60 is not exposed to the metal vapor, and therefore damage to the adhesive 60 is prevented.

[0029] The adhesive 60 is interposed over the entire area between the fourth abutment surface 54 of the cover 13 and the end face 42a of the outer wall portion 42 of the connecting groove 40, the entire area between the third abutment surface 53 of the cover 13 and the inner surface of the outer wall portion 42 of the connecting groove 40, the entire area between the second abutment surface 52 of the cover 13 and the bottom wall 43 of the connecting groove 40, and between the first abutment surface 51 of the cover 13 and the outer surface of the inner wall portion 41 of the connecting groove 40 up to a position approximately identical to the axial dimension H2 of the outer wall portion 42, and since the adhesive 60 is interposed over a large adhesive area between the connecting groove 40 of the case 12 and the connecting protrusion 50 of the cover 13, the case 12 and the cover 13 are integrated while ensuring sufficient airtightness.

[0030] Therefore, according to the electromagnetic contactor 11 of this embodiment, even if the sealed container (case 12 and cover 13) is deflected due to an increase in internal pressure when an arc occurs, the inner wall portion 41 and the outer wall portion 42 of the connecting groove 40 of the case 12 are set to the same thickness (T1 = T2), and the amount of deflection of the inner wall portion 41 and the outer wall portion 42 when internal pressure is applied is approximately the same. Therefore, no local stress acts on the adhesive 60 interposed between the connecting protrusion 50 and the connecting groove 40, and no damage such as cracks occurs, so that it is possible to reliably prevent the arc-extinguishing gas from leaking to the outside. Furthermore, even if metal vapor is generated by the occurrence of an arc, the adhesive 60 interposed between the first abutment surface 51 of the cover 13 and the outer surface of the inner wall portion 41 of the connecting groove 40 does not extend to the tip of the inner wall portion 41, and the adhesive 60 is not exposed to the metal vapor, so damage to the adhesive 60 due to the metal vapor can be reliably prevented.

[0031] Furthermore, since adhesive 60 is interposed over a large bonding area between the connecting grooves 40 of the case 12 and the connecting protrusions 50 of the cover 13, the case 12 and the cover 13 can be integrated while ensuring sufficient airtightness. In this embodiment, the connecting grooves 40 are formed in the case 12 and the connecting protrusions 50 are formed in the cover 13, but the same effect can be obtained even if the connecting protrusions 50 are formed in the case 12 and the connecting grooves 40 are formed in the cover 13. Furthermore, although the electromagnetic contactor 11 has been described in which the fixed contactor 14, the movable contactor 15, the contact support 16, and the electromagnet 17 are hermetically housed in the same space of the sealed container made up of the case 12 and the cover 13, the same effects can be obtained even if the sealed container made up of the case 12 and the cover 13 and the electromagnet are housed in separate spaces. [Explanation of symbols]

[0032] 11 Magnetic contactor 12 cases 13 Cover 14 Fixed contact 15 Moving contact 16 Contact support 17 Electromagnet 18 Contacts 19 Contact spring 21 spools 22 Plunger 23 Outer Yoke 24 Bottom Yoke 25 Permanent Magnets 26 Auxiliary yoke 27 Back spring 31 Reel 32 coils 34 Sliding collar 35 shaft 36 Armature 40 Connection groove 41 Inner wall 42 Exterior wall 42a End face 43 Bottom wall 50 Connecting ridges 51 1st contact surface 52 Second contact surface 53 Third contact surface 54 4th contact surface 60 Adhesive T1 Inner wall thickness T2 Outer wall thickness H1 Axial dimension of inner wall H2 Axial dimension of outer wall

Claims

1. a pair of fixed contacts having fixed contacts; a movable contactor having a pair of movable contacts that can be brought into contact with and separated from the fixed contacts of the pair of fixed contacts; an electromagnet that drives the movable contact; a sealed container that hermetically houses the pair of fixed contacts and the movable contact, the sealed container is made of a synthetic resin and includes a first member and a second member, and is filled with an arc-extinguishing gas; the first member is surrounded by a side wall on an entire periphery, and a connecting ridge is formed continuously on an end surface of the side wall on the entire periphery, the second member has a continuous connecting groove formed at a position facing the end surface of the side wall, into which the connecting protrusion can be inserted; the connecting groove includes an annular inner wall portion, an annular outer wall portion having the same thickness as the inner wall portion and provided outside the inner wall portion, and an annular bottom wall connecting the inner wall portion and bases of the outer wall portion, A sealed electromagnetic contactor characterized in that the first member and the second member are integrated by inserting the connection protrusion into the connection groove and interposing a connection member between the inner wall portion, the outer wall portion and the bottom wall of the connection groove and the connection protrusion facing these.

2. a pair of fixed contacts having fixed contacts; a movable contactor having a pair of movable contacts that can be brought into contact with and separated from the fixed contacts of the pair of fixed contacts; an electromagnet unit that drives the movable contact; a sealed container that houses the pair of fixed contacts, the movable contact, and the electromagnet in the same space, the sealed container is made of a synthetic resin and includes a first member and a second member, and is filled with an arc-extinguishing gas; the first member is surrounded by a side wall on an entire periphery, and a connecting ridge is formed continuously on an end surface of the side wall on the entire periphery, the second member has a continuous connecting groove formed at a position facing the end surface of the side wall, into which the connecting protrusion can be inserted; the connecting groove includes an annular inner wall portion, an annular outer wall portion having the same thickness as the inner wall portion and provided outside the inner wall portion, and an annular bottom wall connecting the inner wall portion and bases of the outer wall portion, A sealed electromagnetic contactor characterized in that the first member and the second member are integrated by inserting the connection protrusion into the connection groove and interposing a connection member between the inner wall portion, the outer wall portion and the bottom wall of the connection groove and the connection protrusion facing these.

3. 3. A sealed electromagnetic contactor according to claim 1 or 2, characterized in that the axial dimension of the inner wall portion of the connection groove is longer than the axial dimension of the outer wall portion, and the connection member is not interposed up to the tip of the inner wall portion, but is interposed up to a position approximately identical to the axial dimension of the outer wall portion.

4. The connection protrusion has a first abutment surface that can abut against the surface of the inner wall portion facing the outer wall portion when inserted into the connection groove, a second abutment surface that can abut against the bottom wall, a third abutment surface that can abut against the surface of the outer wall portion facing the inner wall portion, and a fourth abutment surface that can abut against an end surface of the outer wall portion, and the connection member is interposed between the first abutment surface, the second abutment surface, the third abutment surface, and the fourth abutment surface and the inner wall portion, the bottom wall, and the outer wall portion of the connection groove.

Images