Electromagnetic contactor

Abstract

To provide an electromagnetic contactor capable of preventing intrusion of foreign matters such as metal wear powder generated on a contact point into a sliding portion of a movable plunger.SOLUTION: An electromagnet unit 3 in an electromagnetic contactor 1 includes: a movable plunger 21 for driving a movable contact 13; a contact support 14 for supporting the movable contact 13 and connected to the movable plunger 21; and a spool 24, the spool 24 having a body portion 24a that surrounds an outer circumference of the movable plunger 21 and is wound with an excitation coil 25, and a contact support surrounding portion 24d that surrounds an outer circumference of the contact support 14. The movable plunger 21 is provided with a foreign matter entry prevention member 28 for closing a gap δ between the contact support 14 and the contact support surrounding portion 24d of the spool 24 and preventing foreign matters from entering a sliding portion Δ1 of the movable plunger 21 through the gap δ.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to an electromagnetic contactor that opens and closes a current path. [Background technology]

[0002] 2. Description of the Related Art Conventionally, an electromagnetic contactor for opening and closing a current path has been known, for example, as disclosed in Patent Document 1.

[0003] The electromagnetic contactor shown in Patent Document 1 is an electromagnetic contactor that allows an AC electromagnet and a DC electromagnet to be connected to a common contact support, and includes an electromagnet consisting of either an AC electromagnet having a movable core or a DC electromagnet having an armature, and a contact support that aligns and holds a plurality of movable contacts that are connected to and driven by the electromagnet. The contact support has a connecting portion that is composed of a movable core contact portion, a connecting spring tip storage portion, and an armature contact portion formed on the opposite side of the connecting spring tip storage portion to the movable core contact portion. The AC electromagnet has a connecting spring for the AC electromagnet that is inserted into a through hole formed on the mounting surface side of the movable core, and the contact support and the movable core of the AC electromagnet are connected by this connecting spring for the AC electromagnet. In addition, the DC electromagnet has a connecting spring for the DC electromagnet arranged on a contact surface that contacts the armature contact portion of the armature, and the contact support and the armature provided on the plunger of the DC electromagnet are connected by this spring for the DC electromagnet. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] International Publication No. 2015 / 177956 Summary of the Invention [Problem to be solved by the invention]

[0005] In an electromagnetic contactor using an AC electromagnet or a DC electromagnet, when a movable contactor repeatedly comes into contact with and separates from a pair of fixed contactors, metal wear powder is generated at the contact points. If foreign matter such as this metal wear powder gets into the sliding part between the movable plunger and the spool around which the excitation coil is wound, particularly in an electromagnetic contactor using a DC electromagnet, it will interfere with the driving of the movable plunger and adversely affect the contact and separation action of the movable contactor with respect to the fixed contactor.

[0006] In the electromagnetic contactor shown in Patent Document 1, even when a DC electromagnet is used and a contact support and an armature provided on the plunger of the DC electromagnet are connected by a connecting spring for the DC electromagnet, foreign matter such as metal wear powder generated at the contact point can enter the sliding part between the plunger and the spool around which the excitation coil is wound, causing problems in driving the plunger and adversely affecting the contact and separation action of the movable contact with respect to the fixed contact. The present invention has been made to solve the problems of the conventional art, and its object is to provide an electromagnetic contactor that can prevent foreign matter, such as metal wear powder generated at the contacts, from entering the sliding portion of the movable plunger. [Means for solving the problem]

[0007] In order to achieve the above-mentioned object, an electromagnetic contactor according to one embodiment of the present invention comprises a contact mechanism having a pair of fixed contacts spaced a predetermined distance apart and a movable contactor that can be brought into contact with and separated from the pair of fixed contacts, and an electromagnet unit that drives the movable contactor of the contact mechanism, the electromagnet unit comprising a movable plunger that drives the movable contactor, a contact support that supports the movable contactor and connects it to the movable plunger, and a spool that surrounds the outer periphery of the movable plunger and has a body wound with an excitation coil and a contact support surrounding portion that surrounds the outside of the contact support, and the movable plunger is provided with a foreign object intrusion prevention member that closes the gap between the contact support and the contact support surrounding portion of the spool and prevents foreign objects from intruding through the gap into the sliding portion of the movable plunger in the body.

[0008] Moreover, an electromagnetic contactor according to another aspect of the present invention comprises a contact mechanism having a pair of fixed contacts spaced apart by a predetermined distance and a movable contact that can be brought into contact with and separated from the pair of fixed contacts, and an electromagnet unit that drives the movable contact of the contact mechanism, wherein the electromagnet unit comprises a movable plunger that drives the movable contact, and a spool that surrounds the outer periphery of the movable plunger and has a body around which an excitation coil is wound, wherein an annular positioning protrusion is formed on the inner periphery of the body for positioning a cylindrical plunger ring made of a magnetic material that forms a magnetic path when the excitation coil is excited, and a cylindrical sliding collar made of a non-magnetic material that guides the movement of the movable plunger, and the positioning protrusion is provided with a foreign object accommodating pocket that accommodates foreign objects that have entered between the inner periphery of the plunger ring and the outer periphery of the movable plunger, and prevents the foreign objects from entering the sliding portion of the movable plunger that is formed between the sliding collar and the movable plunger. Effect of the Invention

[0009] According to the electromagnetic contactor of the present invention, it is possible to provide an electromagnetic contactor that can prevent foreign matter such as metal wear powder generated at the contacts from entering the sliding portion of the movable plunger. [Brief description of the drawings]

[0010] [Figure 1] 1 is a perspective view of an electromagnetic contactor according to a first embodiment of the present invention. [Diagram 2] FIG. 2 is a cross-sectional view taken along line 2-2 in FIG. [Diagram 3] 3 is a diagram for explaining a guide gap between a sliding collar and a movable plunger and a ring gap between a plunger ring and the movable plunger in FIG. 2. FIG. [Figure 4] FIG. 2 is a perspective view showing a state in which a movable contact is supported by an electromagnet unit. [Diagram 5] FIG. [Figure 6]1 is a perspective view of a movable plunger having an armature fixed to its lower end and a foreign matter intrusion prevention member crimped together with a connecting spring to its upper end. FIG. [Figure 7] FIG. [Figure 8] FIG. [Figure 9] 9 is a cross-sectional view taken along line 9-9 in FIG. 7. [Figure 10] This may be a cross-sectional view taken along line 10-10 in FIG. [Figure 11] 5 is a cross-sectional view similar to FIG. 2 of an electromagnetic contactor according to a second embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] Hereinafter, embodiments of the present invention will be described with reference to the drawings. The following embodiments are merely examples of devices and methods for embodying the technical idea of ​​the present invention, and the technical idea of ​​the present invention does not limit the materials, shapes, structures, arrangements, etc. of the components to those described below. The technical idea of ​​the present invention can be modified in various ways within the technical scope defined by the claims.

[0012] It should be noted that the drawings are schematic, and that the relationship between thickness and planar dimensions, the thickness ratio of each layer, etc., may differ from the actual ones. Therefore, the specific thicknesses and dimensions should be determined by taking into consideration the following explanation. Furthermore, it goes without saying that the drawings include parts in which the dimensional relationships and ratios differ from one another. (First embodiment) An electromagnetic contactor according to a first embodiment of the present invention is shown in Fig. 1 to Fig. 11. The electromagnetic contactor 1 shown in Fig. 1 and Fig. 2 opens and closes a current path, and includes a contact mechanism 2 and an electromagnet unit 3 that drives a movable contact 13 of the contact mechanism 2. The terms indicating the directions such as "up", "down", "left", "right", "front" and "rear" described in the following specification are defined based on the directions indicated by the arrows in Fig. 1, Fig. 2 and Fig. 11.

[0013] The contact mechanism 2 and the electromagnet unit 3 are housed in a sealed state within a housing case 6. The housing case 6 is made up of an upper case 4 and a lower case 5 which is joined to the upper case 4 by adhesive. Arc-extinguishing gas is enclosed within the housing case 6 through a gas inlet pipe 35. After the arc-extinguishing gas is enclosed within the housing case 6, the gas inlet pipe 35 is cut midway and the opening is closed. The upper case 4 of the housing case 6 is provided with an attachment portion 7 for attaching to another member. The contact mechanism 2 comprises a pair of fixed contacts 11, 12 (hereinafter referred to as the first fixed contact 11 and the second fixed contact 12) fixed to the upper case 4 by insert molding, and a movable contact 13 that can be brought into contact with and separated from the first fixed contact 11 and the second fixed contact 12.

[0014] Each of the first fixed contact 11 and the second fixed contact 12 is made of a conductive metal material and fixed at a predetermined distance in the left-right direction to the upper case 4. A contact 11a is formed on the lower end surface of the first fixed contact 11 on the left side, and a contact 12a is formed on the lower end surface of the second fixed contact 12 on the right side.

[0015] The movable contactor 13 is a conductive plate made of conductive metal and extending long in the left-right direction, and is supported by a contact support 14, a contact spring 16, and a spring presser 15, which are connected to a movable plunger 21 (described later) of the electromagnet unit 3. A contact 13a that contacts a contact 11a of the first fixed contactor 11 on the left side is formed on the upper surface of the left end side of the movable contactor 13, and a contact 13b that contacts a contact 12a of the second fixed contactor 12 on the right side is formed on the upper surface of the right end side of the movable contactor 13.

[0016] The contact support 14 supports the movable contact 13 and connects it to the movable plunger 21, and includes a rectangular flat board portion 14a, a spring accommodating recess 14b formed on the upper surface of the board portion 14a, and a connecting spring support portion 14c formed on the lower surface of the board portion 14a, as shown in Figures 2 and 4. The connecting spring support portion 14c of the contact support 14 is supported by a connecting spring 23 attached to the upper end of the movable plunger 21, and the contact support 14 is connected to the movable plunger 21.

[0017] 4, the spring holder 15 has a flat top plate portion 15a and a pair of legs 15b extending downward from the front and rear edges of the top plate portion 15a. The spring holder 15 is attached to the contact support 14 by attaching the pair of legs 15b to the spring accommodating recess 14b of the contact support 14.

[0018] The movable contactor 13 is arranged so as to penetrate in the left-right direction between the top plate portion 15a of the spring holder 15 and the contact support 14, and is constantly biased upward by the contact spring 16 housed in the spring accommodating recess 14b of the contact support 14, and is clamped between the top plate portion 15a of the spring holder 15 and the contact spring 16, thereby being supported.

[0019] The contact mechanism 2 is placed in an arc-extinguishing container 17 which contains a permanent magnet (not shown) that drives the arc that is generated when the movable contact 13 is separated from the first fixed contact 11 and the second fixed contact 12 to open the contacts.

[0020] Next, as shown in Fig. 2, the electromagnet unit 3 includes a movable plunger 21 that drives the movable contact 13 to move it in the vertical direction. As shown in Figs. 2 and 6, the movable plunger 21 is a round shaft-shaped member that is made of a magnetic material and extends in the vertical direction, and moves upward by exciting an exciting coil 25 described later, and moves downward by releasing the excitation state of the exciting coil 25. As shown in Figs. 2, 5, and 6, a connecting spring 23 is crimped and fastened to the upper end of the movable plunger 21, and an armature 22 made of a disk-shaped magnetic material with a diameter larger than that of the movable plunger 21 is fixed to the lower end of the movable plunger 21. The contact support 14 described above is connected to the movable plunger 21 via the connecting spring 23, and moves upward when the movable plunger 21 moves upward, and moves downward when the movable plunger 21 moves downward. As the contact support 14 moves upward, the movable contact 13 moves upward, and as the contact support 14 moves downward, the movable contact 13 moves downward.

[0021] The vertical position of the armature 22 is lower than the lower surface of the lower plate portion 31ac of the left yoke half 31a and the lower surface of the lower plate portion bc of the right yoke half 31b that constitute the sliding collar 26 and the yoke 31, which will be described later, and is higher than the upper surface of the auxiliary yoke 32, which will be described later. The upward movement of the movable plunger 21 is restricted by the armature 22 abutting against the lower surface of the lower plate portion ac of the left yoke half 31a and the lower surface of the lower plate portion bc of the right yoke half 31b that constitute the yoke 31, and the downward movement of the movable plunger 21 is restricted by the armature 22 abutting against the upper surface of the auxiliary yoke 32, which will be described later.

[0022] The electromagnet unit 3 also includes the contact support 14 and a spool 24. As shown in Figs. 2 to 5 and 7 to 10, the spool 24 has a cylindrical body 24a that surrounds the outer periphery of the movable plunger 21 and extends in the vertical direction. The spool 24 also includes a rectangular plate-shaped upper flange 24b provided at the upper end of the body 24a and protruding from the body 24a in the radial direction of the body 24a, and a rectangular plate-shaped lower flange 24c provided at the lower end of the body 24a and protruding from the body 24a in the radial direction of the body 24a. The spool 24 also includes a contact support surrounding portion 24d provided at the upper flange portion 24b and a yoke lower fixed portion 24e provided at the lower flange portion 24c. The spool 24 is integrally formed by molding an insulating synthetic resin. The contact support surrounding portion 24d has a structure in which the upper plate portion 31ab of the left yoke half 31a and the upper plate portion 31bb of the right yoke half 31b can be press-fitted and fixed from the left and right directions, and is a structure that stands up from the upper flange portion 24b, as shown in Figures 2, 4, 5, 7, 9, and 10. An opening 24da that surrounds the outside of the base plate portion 14a and the connecting spring support portion 14c of the contact support 14 is formed in the top plate portion of the contact support surrounding portion 24d. A gap δ is formed between the opening 24da of the contact support surrounding portion 24d and the base plate portion 14a and the connecting spring support portion 14c of the contact support 14, as shown in Figures 2 and 4. The reason for forming this gap δ is to allow the contact support 14 to move up and down smoothly without being hindered by the contact support surrounding portion 24d in accordance with the up and down movement of the movable plunger 21.

[0023] An exciting coil 25 for driving the movable plunger 21 is wound around the outer periphery of the body 24a of the spool 24. The exciting coil 25 is electrically connected to a terminal 36. A positioning protrusion 24f is formed in the approximate center in the up-down direction of the body 24a of the spool 24, protruding radially inward to position a sliding collar 26 and a plunger ring 27 (described later) that are installed on the inner periphery of the body 24a.

[0024] The electromagnet unit 3 also includes a non-magnetic cylindrical sliding collar 26 that guides the movement of the movable plunger 21 and is installed on the inner circumference of the body 24a of the spool 24 with a guide gap Δ1 (see FIG. 3, maximum 2Δ1 in the circumferential direction) between the collar and the outer circumference of the movable plunger 21.

[0025] The sliding collar 26 is fixed by press fitting to the inner circumference of the body 24a of the spool 24 below the positioning protrusion 24f. The upper end surface of the sliding collar 26 is positioned by abutting against the positioning protrusion 24f provided on the body 24a. By installing the sliding collar 26 on the inner circumference of the body 24a of the spool 24 with a guide gap Δ1 between it and the outer circumference of the movable plunger 21, it is possible to suppress dimensional changes in the body 24a when the exciting coil 25 is wound around the outer circumference of the body 24a of the spool 24, and it is possible to obtain an effect of improving the guiding performance of the movement of the movable plunger 21.

[0026] The electromagnet unit 3 also includes a cylindrical magnetic plunger ring 27 that is installed on the inner periphery of the body 24a of the spool 24 with a ring gap Δ2 (see FIG. 3, maximum 2Δ2 in the circumferential direction) larger than the guide gap Δ1 between the outer periphery of the movable plunger 21 and the magnetic pole. The plunger ring 27 is fixed by press-fitting to the inner periphery above the positioning protrusion 24f of the body 24a of the spool 24. The lower end surface of the plunger ring 27 is positioned by abutting against the positioning protrusion 24f provided on the body 24a. The cylindrical magnetic plunger ring 27 that forms a magnetic path when the magnetic pole 25 is excited is installed on the inner periphery of the body 24a of the spool 24 with a ring gap Δ2 between the outer periphery of the movable plunger 21 and the magnetic pole. As a result, when the excitation coil 25 is excited, a magnetic path is formed in the plunger ring 27 between the upper plate portions 31ab, 31bb of the yoke 31 described later and the movable plunger 21, making it easier for the armature 22 fixed to the movable plunger 21 to be attracted to the lower plate portions 31ac, 31bc of the yoke 31, and an appropriate magnetic force is generated to enable the movable plunger 21 to be driven (moved upward) smoothly.

[0027] Furthermore, since the ring gap Δ2 between the inner surface of the plunger ring 27 and the outer surface of the movable plunger 21 is larger than the guide gap Δ1 between the inner surface of the sliding collar 26 and the outer surface of the movable plunger 21, there is little risk that the movable plunger 21 will be attracted to the plunger ring 27 and become unable to move when the exciting coil 25 is excited.

[0028] The electromagnet unit 3 also includes a yoke 31 consisting of a left yoke half 31a and a right yoke half 31b having a symmetrical shape. The left yoke half 31a is made of a magnetic material, and includes a vertically extending flat plate portion 31aa extending in the vertical direction outside the left-right direction of the exciting coil 25, an upper plate portion 31ab extending from an upper end of the vertically extending flat plate portion 31aa toward the plunger ring 27, and a lower plate portion 31ac extending from a lower end of the vertically extending flat plate portion 31aa toward the movable plunger 21, as shown in Figs. 2, 4, and 5. The upper plate portion 31ab of the left yoke half 31a is press-fitted and fixed to the contact support surrounding portion 24d of the spool 24 so as to abut against the plunger ring 27, and the lower plate portion 31ac of the left yoke half 31a is press-fitted and fixed to the yoke lower fixed portion 24e of the spool 24. 2, the right yoke half 31b is provided with a vertically extending flat plate portion 31ba extending in the vertical direction outside the left-right direction of the exciting coil 25, an upper plate portion 31bb extending from an upper end of the vertically extending flat plate portion 31ba toward the plunger ring 27, and a lower plate portion 31bc extending from a lower end of the vertically extending flat plate portion 31ba toward the movable plunger 21. The upper plate portion 31bb of the right yoke half 31b is press-fitted and fixed into the contact support surrounding portion 24d of the spool 24 from the opposite side of the left yoke half 31a so as to abut against the plunger ring 27, and the lower plate portion 31bc of the right yoke half 31b is press-fitted and fixed into the yoke lower fixed portion 24e of the spool 24 from the opposite side of the left yoke half 31a.

[0029] An annular permanent magnet 33 is provided around the armature 22 provided on the movable plunger 21 below the lower plate portion 31ac of the left yoke half 31a and the lower plate portion 31bc of the right yoke half 31b of the yoke 31. An annular plate-shaped auxiliary yoke 32 made of a magnetic material is provided below the permanent magnet 33. The permanent magnet 33 is attached to the lower surfaces of the lower plate portion 31ac of the left yoke half 31a and the lower plate portion 31bc of the right yoke half 31b, and the auxiliary yoke 32 is installed in a state of being attached to the lower surface of the permanent magnet 33.

[0030] The electromagnet unit 3 also includes a return spring 34 that separates the movable contact 13 from the first fixed contact 11 and the second fixed contact 12 when the excitation coil 25 is released from an excited state. The return spring 34 is disposed between the lower end surface 26a of the sliding collar 26 and the armature 22 fixed to the movable plunger 21 so as to surround the movable plunger 21. When the excitation coil 25 is in an excited state, the armature 22 fixed to the movable plunger 21 is attracted to the lower surfaces of the lower plate portion ac of the left yoke half 31a and the lower plate portion bc of the right yoke half 31b of the yoke 31, and the movable contact 13 is in contact with the first fixed contact 11 and the second fixed contact 12 by the contact pressure of the contact spring 16. When the excitation coil 25 is released in this state, the armature 22 fixed to the movable plunger 21 descends due to the spring force of the return spring 34, and the armature 22 is attracted to the upper surface of the auxiliary yoke 32 by the action of the permanent magnet 33. As the movable plunger 21 and armature 22 descend, the movable contactor 13 descends together with the contact support 14, spring holder 15, and contact spring 16 connected to the movable plunger 21 via the connecting spring 23, and the movable contactor 13 opens away from the first fixed contactor 11 and the second fixed contactor 12.

[0031] In the electromagnetic contactor 1 having such a configuration, when the movable contact 13 repeatedly comes into contact with and separates from the first fixed contact 11 and the second fixed contact 12, metal wear powder is generated at the contacts 11a, 13a, 12a, and 13b. This metal wear powder and other foreign matter may fall through the gap δ formed between the opening 24da of the contact support surrounding portion 24d and the base plate portion 14a and the connecting spring support portion 14c of the contact support 14, pass through the ring gap Δ2 between the inner peripheral surface of the plunger ring 27 and the outer peripheral surface of the movable plunger 21, and enter the guide gap Δ1 (sliding portion of the movable plunger 21) between the inner peripheral surface of the sliding collar 26 and the outer peripheral surface of the movable plunger 21. If the foreign matter enters the guide gap Δ1 (the sliding portion of the movable plunger 21), it will interfere with the up and down movement of the movable plunger 21, and will have an adverse effect on the contact and separation operation of the movable contact 13 with respect to the first fixed contact 11 and the second fixed contact 12.

[0032] In order to prevent such foreign matter from entering the sliding portion of the movable plunger 21, in the electromagnetic contactor 1 according to the first embodiment, a foreign matter entry prevention member 28 is provided on the movable plunger 21. The foreign matter entry prevention member 28 closes the gap δ formed between the opening 24da of the contact support surrounding portion 24d and the base plate portion 14a and the connecting spring support portion 14c of the contact support 14, and prevents foreign matter from entering from this gap δ into the guide gap Δ1 (sliding portion of the movable plunger 21) between the inner peripheral surface of the sliding collar 26 and the outer peripheral surface of the movable plunger 21.

[0033] 2, 5 and 6, the foreign matter intrusion prevention member 28 is a thin circular polyester film having a diameter larger than the longitudinal dimension of the opening 24da of the contact support surrounding portion 24d, and is crimped (fixed) together with the connecting spring 23 to the upper end of the movable plunger 21 and the lower side of the connecting spring 23. As shown in Figs. 2, 4 and 5, the foreign matter intrusion prevention member 28 is disposed below the top plate portion that forms the opening 24da of the contact support surrounding portion 24d. In this embodiment, the foreign matter intrusion prevention member 28 is Lumirror (registered trademark), but may be made of a polyester film other than Lumirror (registered trademark) or heat-resistant paper so as to be smoothly deformed when moving up and down together with the movable plunger 21.

[0034] The movable plunger 21 is provided with a foreign matter intrusion prevention member 28 that closes the gap δ between the contact support 14 and the contact support surrounding portion 24d of the spool 24 and prevents foreign matter from intruding from this gap δ into a guide gap Δ1 (sliding portion of the movable plunger 21) between the inner peripheral surface of the sliding collar 26 and the outer peripheral surface of the movable plunger 21. As a result, foreign matter such as metal wear powder generated at the contacts 11a, 13a, 12a, and 13b is prevented from moving downward through the gap δ between the contact support 14 and the contact support surrounding portion 24d of the spool 24 by the foreign matter intrusion prevention member 28, and thus it is possible to prevent foreign matter from intruding into the guide gap Δ1 (sliding portion of the movable plunger 21) located below.

[0035] 2, 3, 7, and 9, in the electromagnetic contactor 1 according to the first embodiment, an annular positioning protrusion 24f is formed on the inner periphery of the body 24a of the spool 24 for positioning the cylindrical magnetic plunger ring 27 that forms a magnetic path when the exciting coil 25 is excited, and the cylindrical non-magnetic sliding collar 26 that guides the movement of the movable plunger 21. In addition, a foreign object storage pocket 29 is formed in the positioning protrusion 24f for storing foreign objects that have entered between the inner periphery of the plunger ring 27 and the outer periphery of the movable plunger 21, as shown in FIGS. 2, 3, 7, 9, and 10.

[0036] As shown in Figures 7 to 9, three foreign object containing pockets 29 are provided at equal intervals in the circumferential direction of the annular positioning protrusion 24f, and each foreign object containing pocket 29 is formed as a recess recessed from the upper surface of the positioning protrusion 24f.

[0037] By forming the foreign object storage pocket 29 in the positioning protrusion 24f, even if the above-mentioned foreign object passes through the foreign object intrusion prevention member 28 and intrudes into the ring gap Δ2 between the inner circumference of the plunger ring 27 and the outer circumference of the movable plunger 21, the foreign object is stored in the foreign object storage pocket 29. Therefore, it is possible to prevent the foreign object from intruding into the guide gap Δ1 (sliding portion of the movable plunger 21) between the inner circumference surface of the sliding collar 26 and the outer circumference surface of the movable plunger 21.

[0038] Next, the operation of the electromagnetic contactor 1 of the first embodiment will be described. Assume now that the first fixed contact 11 is connected to, for example, a power supply source that supplies a large current, and the other second fixed contact 12 is connected to a load device. In this state, as shown in FIG. 2, the excitation coil 25 in the electromagnet unit 3 is in a non-excited state, and the electromagnet unit 3 is in a released state in which it is not generating an excitation force that moves the movable plunger 21 upward.

[0039] In this released state, the movable plunger 21 is biased downward by the return spring 34, and the armature 22 is attracted to the auxiliary yoke 32 by the action of the permanent magnet 33. Therefore, the movable contactor 13 connected to the movable plunger 21 is spaced downward a predetermined distance from the first fixed contactor 11 and the second fixed contactor 12. Therefore, the current path between the first fixed contactor 11 and the second fixed contactor 12 is interrupted, and the contact mechanism 2 is in an open state.

[0040] When current is applied to the excitation coil 25 of the electromagnet unit 3 from this released state, a magnetic path is formed in the movable plunger 21, armature 22, yoke 31 (left yoke half 31a and right yoke half 31b), plunger ring 27, and movable plunger 21, and an excitation force is generated in the electromagnet unit 3, pushing the movable plunger 21 upward against the attraction force of the permanent magnet 33 to the auxiliary yoke 32 and the biasing force of the return spring 34, and the armature 22 is attracted to the undersides of the lower plate portion ac of the left yoke half 31a and the lower plate portion bc of the right yoke half 31b of the yoke 31.

[0041] In this way, as the movable plunger 21 moves upward, the movable contactor 13 connected to the movable plunger 21 also moves upward, and both contacts 13a, 13b of the movable contactor 13 come into contact with the contact 11a of the first fixed contactor 11 and the contact 12a of the second fixed contactor 12 with the contact pressure of the contact spring 16.

[0042] As a result, a large current from the power supply source is supplied to the load device through the first fixed contact 11, the movable contact 13, and the second fixed contact 12, and the contact mechanism 2 is brought into a closed state. When the current supply to the load device is to be cut off from the state in which the contact mechanism 2 is closed, the current supply to the exciting coil 25 of the electromagnet unit 3 is stopped.

[0043] When the current to the excitation coil 25 is stopped, the excitation force that moves the movable plunger 21 upward in the electromagnet unit 3 is lost, so that the movable plunger 21 descends due to the biasing force of the return spring 34, and the armature 22 is attracted to the auxiliary yoke 32 by the action of the permanent magnet 33.

[0044] As the movable plunger 21 descends, the movable contactor 13 connected to the movable plunger 21 descends. When contact pressure is applied by the contact spring 16 in response to this, the movable contactor 13 is in contact with the first fixed contactor 11 and the second fixed contactor 12. Thereafter, when the contact pressure of the contact spring 16 is released, the movable contactor 13 moves downward away from the first fixed contactor 11 and the second fixed contactor 12, entering an opening start state.

[0045] When this opening start state is reached, an arc is generated between both contacts 13a, 13b of the movable contactor 13 and the contact 11a of the first fixed contactor 11 and the contact 12a of the second fixed contactor 12, and the arc continues to flow current.

[0046] This arc is driven by a permanent magnet (not shown) installed in the arc-extinguishing container 17 and is extinguished in the arc-extinguishing container 17. Then, when the armature 22 fixed to the movable plunger 21 is attracted to the auxiliary yoke 32 by the action of the permanent magnet 33, the releasing operation of the movable plunger 21 is completed, and the opening of the contacts is completed.

[0047] Here, according to the electromagnetic contactor 1 of the first embodiment, as described above, the movable plunger 21 is provided with a foreign object intrusion prevention member 28 that blocks the gap δ between the contact support 14 and the contact support surrounding portion 24d of the spool 24 and prevents foreign objects from intruding from this gap δ into the guide gap Δ1 (sliding portion of the movable plunger 21) between the inner surface of the sliding collar 26 and the outer surface of the movable plunger 21.

[0048] As a result, foreign matter such as metal wear powder generated at the contacts 11a, 13a, 12a, and 13b is prevented from moving downward through the gap δ between the contact support 14 and the contact support surrounding portion 24d of the spool 24 by the foreign matter intrusion prevention member 28, and is prevented from invading the guide gap Δ1 (sliding portion of the movable plunger 21) located below.

[0049] Furthermore, according to the electromagnetic contactor 1 of the first embodiment, as described above, the annular positioning protrusion 24f is formed on the inner periphery of the body 24a of the spool 24 for positioning the cylindrical magnetic plunger ring 27 that forms a magnetic path when the exciting coil 25 is excited, and the cylindrical non-magnetic sliding collar 26 that guides the movement of the movable plunger 21. Then, the positioning protrusion 24f is formed with a foreign object storage pocket 29 that stores foreign objects that have entered between the inner periphery of the plunger ring 27 and the outer periphery of the movable plunger 21.

[0050] As a result, even if the above-mentioned foreign matter passes through the foreign matter intrusion prevention member 28 and intrudes into the ring gap Δ2 between the inner circumference of the plunger ring 27 and the outer circumference of the movable plunger 21, the foreign matter is accommodated in the foreign matter accommodation pocket 29. Therefore, it is possible to prevent the foreign matter from intruding into the guide gap Δ1 between the inner circumference surface of the sliding collar 26 and the outer circumference surface of the movable plunger 21 (the sliding portion of the movable plunger 21). Second embodiment Next, an electromagnetic contactor according to a second embodiment of the present invention will be described with reference to Fig. 11. In Fig. 11, the same members as those shown in Fig. 2 are given the same reference numerals, and their description may be omitted.

[0051] The electromagnetic contactor according to the second embodiment of the present invention has a basic structure similar to that of the electromagnetic contactor 1 according to the first embodiment shown in FIGS. 1 to 10, but differs in that the foreign matter intrusion prevention member 28 is not crimped and fastened to the movable plunger 21.

[0052] In other words, in order to prevent foreign matter from entering the guide gap Δ1 (sliding portion of the movable plunger 21) between the inner surface of the sliding collar 26 and the outer surface of the movable plunger 21, a foreign matter containing pocket 29 is simply formed in the positioning protrusion 24f to contain foreign matter that has entered between the inner circumference of the plunger ring 27 and the outer circumference of the movable plunger 21.

[0053] Similar to those shown in Figures 7 to 9, three foreign object containing pockets 29 are provided at equal intervals around the circumference of the annular positioning protrusion 24f, and each foreign object containing pocket 29 is formed by a recess recessed from the upper surface of the positioning protrusion 24f.

[0054] According to the electromagnetic contactor 1 of the second embodiment, by forming a foreign object storage pocket 29 in the positioning protrusion 24f to store foreign objects that have entered between the inner periphery of the plunger ring 27 and the outer periphery of the movable plunger 21, when a foreign object enters from the gap δ into the ring gap Δ2 between the inner periphery of the plunger ring 27 and the outer periphery of the movable plunger 21, the foreign object is stored in the foreign object storage pocket 29. Therefore, it is possible to prevent foreign objects from entering the guide gap Δ1 between the inner periphery of the sliding collar 26 and the outer periphery of the movable plunger 21 (the sliding portion of the movable plunger 21).

[0055] Although the embodiment of the present invention has been described above, the present invention is not limited to this and various modifications and improvements can be made. For example, in the electromagnetic contactor 1 according to the first embodiment, the shape of the foreign matter intrusion prevention member 28 is not limited to a thin circular plate.

[0056] Furthermore, in the electromagnetic contactors 1 according to the first and second embodiments, the number of foreign object containing pockets 29 is not limited to three, and the shape thereof is not limited to the example shown in the drawings.

[0057] Furthermore, in the electromagnetic contactor 1 according to the first embodiment, the foreign object receiving pocket 29 does not need to be formed in the positioning protrusion 24f.

[0058] Furthermore, in the electromagnetic contactor 1 of the first embodiment, the sliding collar 26 and the plunger ring 27 may not be provided, and the positioning protrusion 24f may not be formed on the body 24a of the spool 24, and a foreign object intrusion prevention member 28 may be used to prevent foreign objects from intruding into the gap between the body 24a of the spool 24 and the movable plunger 21 (the sliding portion of the movable plunger 21). [Explanation of symbols]

[0059] 1 Magnetic contactor 2 Contact mechanism 3 Electromagnet Unit 4 Upper case 5 Lower case 6 Storage Case 7 Mounting part 11 1st fixed contact (fixed contact) 11a Contact 12 2nd fixed contact (fixed contact) 12a Contact 13 Movable contact 13a Contact 13b Contact 14 Contact support 14a Substrate section 14b Spring receiving recess 14c Connecting spring support part 15 Spring retainer 16 Contact Spring 17 Arc-extinguishing vessel 21 Movable plunger 22 Armature 23 Connecting spring 24 spools 24a Torso 24b Upper flange 24c Lower flange 24d Contact support enclosure 24e Lower yoke fixing part 24f Positioning protrusion 25 Excitation coil 26 Sliding collar 26a Lower end surface (end surface) 27 Plunger Ring 28 Foreign object intrusion prevention member 29 Foreign object storage pocket 31 York 31a Left yoke half 31aa Vertical stretched flat plate part 31ab Upper plate 31ac lower plate part 31b Right yoke half 31ba Upper and lower stretched flat plate section 31bb Upper plate 31bc lower plate part 32 Auxiliary yoke 33 Permanent Magnets 34 Return spring 35 Gas inlet pipe 36 Terminals Δ1 Guide gap (sliding part of movable plunger) Δ2 Ring gap

Claims

1. An electromagnetic contactor comprising: a contact mechanism having a pair of fixed contacts spaced apart by a predetermined distance and a movable contact that can be brought into contact with and separated from the pair of fixed contacts; and an electromagnet unit that drives the movable contact of the contact mechanism, the electromagnet unit comprising: a movable plunger that drives the movable contact; a contact support that supports the movable contact and connects it to the movable plunger; and a spool that surrounds the outer periphery of the movable plunger and has a body wound with an excitation coil and a contact support surrounding portion that surrounds the outside of the contact support, An electromagnetic contactor characterized in that the movable plunger is provided with a foreign object intrusion prevention member that seals the gap between the contact support and the contact support surrounding portion of the spool, thereby preventing foreign objects from entering through the gap into the sliding portion of the movable plunger in the body portion.

2. 2. The electromagnetic contactor according to claim 1, further comprising an annular positioning protrusion formed on an inner periphery of the body for positioning a cylindrical plunger ring made of a magnetic material that forms a magnetic path when the excitation coil is excited, and a cylindrical sliding collar made of a non-magnetic material that guides the movement of the movable plunger, and a foreign object storage pocket for storing the foreign object that has entered between the inner periphery of the plunger ring and the outer periphery of the movable plunger is provided on the positioning protrusion.

3. 3. The electromagnetic contactor according to claim 1, wherein the foreign matter intrusion prevention member is a polyester film.

4. 4. The electromagnetic contactor according to claim 1, wherein the foreign object intrusion prevention member is fixed to the movable plunger by crimping.

5. An electromagnetic contactor comprising: a contact mechanism having a pair of fixed contacts spaced apart by a predetermined distance and a movable contact that can be brought into contact with and separated from the pair of fixed contacts; and an electromagnet unit that drives the movable contact of the contact mechanism, the electromagnet unit comprising a movable plunger that drives the movable contact, and a spool that surrounds the outer periphery of the movable plunger and has a body around which an excitation coil is wound, an annular positioning protrusion is formed on the inner periphery of the body for positioning a cylindrical plunger ring made of a magnetic material which forms a magnetic path when the excitation coil is excited, and a cylindrical sliding collar made of a non-magnetic material which guides the movement of the movable plunger, and a foreign object accommodating pocket is provided on the positioning protrusion for accommodating foreign objects which have entered between the inner periphery of the plunger ring and the outer periphery of the movable plunger, thereby preventing the intrusion of foreign objects into the sliding portion of the movable plunger which is formed between the sliding collar and the movable plunger.

Images