JP7294111B2 - magnetic contactor - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electromagnetic contactor that opens and closes a current path by connecting and separating fixed contacts of a pair of fixed contacts and a pair of movable contacts of a movable contact.

As an electromagnetic contactor that opens and closes a current path, for example, one described in Patent Document 1 is known.
The electromagnetic contactor of Patent Document 1 includes a contact mechanism including a pair of fixed contacts having fixed contacts and a movable contact having a pair of movable contacts capable of contacting and separating from the fixed contacts, and a drive shaft to the movable contacts. an electromagnet unit having a movable plunger coupled thereto to drive the contact mechanism; and a sealed chamber containing the contact mechanism, drive shaft and movable plunger.

A pair of fixed contacts includes a first conductive plate portion provided with a fixed contact, a second conductive plate portion extending from an end of the first conductive plate portion, and an end portion of the second conductive plate portion. It has a C shape when viewed from the side surface including the third conductive plate portion. In addition, the movable contact is formed of a long conductive plate, and a pair of movable contacts provided at both ends in the longitudinal direction face the fixed contacts provided on the first conductive plate portions of the first and second fixed contacts. are placed.
A through hole through which the drive shaft is inserted is formed in the center of the movable contact in the longitudinal direction. The movable contact is slidably connected to the drive shaft by supporting the lower central part of the movable contact and pressing the upper central part of the movable contact with a contact spring engaged with the upper part of the drive shaft.

In the storage chamber, a space for accommodating the contact mechanism and the movable plunger is partitioned by a partition member through which the drive shaft is inserted. a contact housing case that is joined to the upper surface of the magnetic yoke and accommodates the contact mechanism and the insulating holder therein; and a cap that is joined to the lower surface of the magnetic yoke and accommodates the movable plunger therein. The partition member includes a magnetic yoke, a permanent magnet fixed to the upper surface of the magnetic yoke, and a plate-like auxiliary yoke fixed to the upper surface of the permanent magnet and through which the drive shaft is vertically inserted. Here, the above-described insulating holder is a bottomed cylindrical member molded of an insulating synthetic resin material or the like, and an insertion hole through which the drive shaft is inserted is formed in the bottom.

Japanese Patent No. 6237916

By the way, when the contact mechanism of the electromagnetic contactor repeats the open state and the closed state and the fixed contacts of the pair of fixed contacts and the pair of movable contacts of the movable contact come into contact with each other, the center of the movable contact Metal powder is generated when the lower portion contacts the drive shaft flange portion of the drive shaft.
In Patent Document 1 mentioned above, metal powder generated by contact between the movable contactor and the drive shaft flange may enter the electromagnet unit through a through hole provided in the bottom of the insulating holder, and the metal powder may adhere to the movable plunger. be. If metal powder adheres to the movable plunger, the distance between the fixed contact and the movable contact in the open state becomes shorter than the standard dimension, which adversely affects the breaking performance of the arc generated between the fixed contact and the movable contact. There is a risk. Moreover, if metal powder is interposed between the contact surfaces of the movable plunger and the auxiliary yoke, the magnetic circuit becomes unstable, which may adversely affect the operation. Furthermore, if metal powder enters the clearance between the movable plunger and the cap, there is a risk that the sliding motion of the movable plunger will be hindered.
Therefore, the present invention prevents the metal powder generated in the contact mechanism from entering the electromagnet unit side, does not affect the arc interruption performance generated between the fixed contact and the movable contact, and prevents the operation of the electromagnet unit. The object is to provide an electromagnetic contactor that does not affect.

In order to achieve the above object, an electromagnetic contactor according to an aspect of the present invention includes a pair of fixed contacts having fixed contacts and a pair of movable contacts that can be brought into contact with and separated from the fixed contacts at both ends in the longitudinal direction. A contact mechanism having a movable contact, an electromagnet unit having a drive shaft connected to the movable contact and driving the movable contact in a contacting/separating direction to and from a pair of fixed contacts, a contact mechanism and the drive shaft and an insulating holder, which is a cylindrical member with a bottom and has an insertion hole formed in the bottom for the drive shaft to pass through, and is arranged in the contact storage case. The drive shaft has a drive shaft flange protruding from the outer periphery of the drive shaft, and the movable contactor is slidably supported on the drive shaft with its central portion pressed against the drive shaft flange by a contact spring. At the bottom of the insulating holder, a cylindrical insulating cylinder is formed that rises from the periphery of the opening of the insertion hole and covers the outer periphery of the drive shaft. It is set to a value greater than the dimension.

The present invention can reliably prevent metal powder generated in the contact mechanism from entering the electromagnet unit side, thereby maintaining the performance of interrupting the arc generated between the fixed contact and the movable contact, and the electromagnet. It is possible to provide an electromagnetic contactor that does not affect the operation of the unit.

BRIEF DESCRIPTION OF THE DRAWINGS It is sectional drawing which shows the magnetic contactor of 1st Embodiment which concerns on this invention. BRIEF DESCRIPTION OF THE DRAWINGS It is sectional drawing which expanded and showed the contact mechanism of 1st Embodiment which concerns on this invention. It is sectional drawing which expanded and showed the contact mechanism of the electromagnetic contactor of 2nd Embodiment which concerns on this invention.

Next, embodiments according to the present invention will be described with reference to the drawings. In the following description of the drawings, the same or similar parts are denoted by the same or similar reference numerals. However, it should be noted that the drawings are schematic, and the relationship between thickness and planar dimension, the ratio of thickness of each layer, and the like are different from the actual ones. Therefore, specific thicknesses and dimensions should be determined with reference to the following description. In addition, it is a matter of course that there are portions with different dimensional relationships and ratios between the drawings.
Further, the embodiments shown below are examples of devices and methods for embodying the technical idea of the present invention. etc. are not specified below. Various modifications can be made to the technical idea of the present invention within the technical scope defined by the claims.

[First Embodiment]
1 and 2 show an electromagnetic contactor 1 according to a first embodiment of the invention.
As shown in FIG. 1 , the electromagnetic contactor 1 includes a case body 2 and a case lid portion 3 that closes the lower portion of the case body 2 .
A contact mechanism 4 is arranged inside the upper side of the case body 2 , and an electromagnet unit 5 for driving the contact mechanism 4 is arranged in a space closed by the inside of the lower side of the case body 2 and the case cover 3 .
The contact mechanism 4 is housed in a contact housing case 6 . The contact housing case 6 includes a metal rectangular tube 7 and an insulating substrate 8 made of an insulating material such as ceramic or synthetic resin material, which closes the upper end of the rectangular tube 7 .

The rectangular tube 7 is fixed in a state where a rectangular tube flange portion 7a formed at the bottom thereof is sealingly joined to an upper magnetic yoke 21 of the electromagnet unit 5, which will be described later. Through holes 9 and 10 are formed in the insulating substrate 8 at predetermined intervals.
The contact mechanism 4 includes a pair of stationary contacts 13 and 14 (hereinafter referred to as a first stationary contact 13 and a second stationary contact 14) fixed to an insulating substrate 8 via conductor portions 11 and 12, A movable contact 15 having first and second movable contacts 15a and 15b opposed to the first and second fixed contacts 13a and 14a provided on the first and second fixed contacts 13 and 14 is provided.
The movable contactor 15 is supported by a drive shaft 23 fixed to a movable plunger 22 of the electromagnet unit 5 , and a through hole 24 through which the drive shaft 23 is inserted is formed in the center of the movable contactor 15 .

A circular driving shaft flange portion 25 protruding outward is formed in the central portion of the driving shaft 23 in the longitudinal direction. The center lower portion of the child 15 is brought into contact with the drive shaft flange portion 25 and the contact spring 26 is inserted from the upper portion of the drive shaft 23 . By fixing the upper end of the contact spring 26 with a spring receiver 27a fixed to the upper end of the drive shaft 23 and a C ring 27b, the contact spring 26 applies a predetermined biasing force to the movable contactor 15. .

The electromagnet unit 5 has a flat U-shaped magnetic yoke 28 when viewed from the side. are placed.
The spool 30 includes a central cylindrical portion 31 through which the fixed plunger 29 is inserted, a lower flange portion 32 projecting radially outwardly from the lower end of the central cylindrical portion 31, and a slightly lower side than the upper end of the central cylindrical portion 31. and an upper flange portion 33 projecting radially outward. An exciting coil 34 is wound in a housing space formed by the central cylindrical portion 31 , the lower flange portion 32 and the upper flange portion 33 .

The upper magnetic yoke 21 fixed to the upper open end of the magnetic yoke 28 has a through hole 21a formed in the center thereof, the through hole 21a facing the central cylindrical portion 31 of the spool 30. As shown in FIG.
The upper portion of the fixed plunger 29 inserted into the central cylindrical portion 31 of the spool 30 is covered with a cap 35 formed in a cylindrical shape with a bottom. A flange portion 35a is arranged. The flange portion 35a is sealingly joined to the lower surface of the upper magnetic yoke 21. As shown in FIG. As a result, a sealed container is formed in which the cap 35 communicates with the upper magnetic yoke 21 via the through hole 21a.

A movable plunger 22 is inserted into the cap 35 so as to be vertically slidable. The movable plunger 22 has a peripheral flange 22a projecting radially outward from the upper end projecting upward from the upper magnetic yoke 21. As shown in FIG.
An annular driving permanent magnet 37 is fixed to the upper surface of the upper magnetic yoke 21 so as to surround the peripheral flange 22 a of the movable plunger 22 . The driving permanent magnet 37 is magnetized in the vertical direction, that is, in the thickness direction, such that the upper end side is the N pole and the lower end side is the S pole.

An auxiliary yoke 39 having the same outer shape as the driving permanent magnet 37 and having a through hole 38 with an inner diameter smaller than the outer diameter of the peripheral collar portion 22a of the movable plunger 22 is fixed to the upper end surface of the driving permanent magnet 37. A peripheral flange 22 a of the movable plunger 22 contacts the lower surface of the yoke 39 . Various gases for arc extinguishing are enclosed in the sealed contact housing case 6 .
A back spring 36 is inserted through the drive shaft 23 from below, and is attached to the outer circumference of the drive shaft 23 with one end side of the back spring 36 in contact with the drive shaft flange portion 25 . Then, the lower portion of the drive shaft 23 with the back spring 36 mounted thereon is inserted through the through hole 38 of the auxiliary yoke 39, inserted through the movable plunger 22, and then fixed. As a result, the back spring 36 is arranged between the drive shaft flange portion 25 of the drive shaft 23 and the upper surface of the auxiliary yoke 39 on the inner diameter side, and the back spring 36 is pushed in the direction in which the auxiliary yoke 39 is pressed against the permanent magnet 37 side. A predetermined biasing force acts.

Next, the first stationary contact 13, the second stationary contact 14, and the movable contact 15, which constitute the contact mechanism 4, will be described with reference to FIG.
The first fixed contact 13 is a C-shaped conductive plate in a side view made of a conductive material. fixed through.
The first fixed contact 13 is arranged on the first movable contact 15a side of the movable contact 15, faces the first movable contact 15a of the movable contact 15 from below, and faces the first fixed contact 13a upward. A first conductive plate portion 13b provided, a second conductive plate portion 13c bent from the end of the first conductive plate portion 13b away from the movable contact 15 and extending upward, and a second conductive plate portion a third conductive plate portion 13d that is bent from the upper end of the movable contact 13c and extends above the movable contact 15;

The second fixed contact 14 is arranged on the side of the second movable contact 15b of the movable contact 15, faces the second movable contact 15b of the movable contact 15 from below, and connects the second fixed contact 14a. A first conductive plate portion 14b provided on the upper surface, a second conductive plate portion 14c bent upward from the end of the first conductive plate portion 14b away from the movable contact 15, and a second conductive plate portion 14c. and a third conductive plate portion 14 d that is bent from the upper end of the plate portion 14 c and extends above the movable contact 15 .

A cover 16 made of synthetic resin is attached to the first fixed contactor 13 to restrict arc generation. The second fixed contactor 14 is also fitted with a synthetic resin cover 17 for restricting arc generation. As a result, the first fixed contact 13a and the first conductive plate portion 13b are exposed on the inner peripheral surface of the first fixed contact 13, and the second fixed contact 14a and the second conductive plate portion 13b are exposed on the inner peripheral surface of the second fixed contact 14. 1 conductive plate portion 14b is exposed.
In addition, a C-shaped magnetic body as viewed from the top so as to cover the inner surface of the second conductive plate portion 13c of the first fixed contact 13 and the inner surface of the second conductive plate portion 14c of the second fixed contact 14 Plates 19a and 19b are mounted. Thereby, the magnetic field generated by the current flowing through the second conductive plate portions 13c and 14c can be shielded.

The movable contactor 15 is a linear conductive plate elongated in the left-right direction of FIG. 2 and made of a conductive material. A movable contact 15a and a second movable contact 15b are formed.
A cylindrical insulating holder 18 with a bottom is arranged inside the contact housing case 6 . The insulating holder 18 is made of an insulating synthetic resin that generates hydrogen gas when melted. The insulating holder 18 includes a rectangular cylindrical insulating wall 18a extending along the inner side of the rectangular cylindrical body 7 of the contact housing case 6, an upper magnetic yoke 21 formed below the rectangular cylindrical insulating wall 18a, and a driving permanent magnet. and an insulating bottom portion 18 b that covers the upper surfaces of the magnet 36 and the auxiliary yoke 39 . The insulating bottom portion 18b is formed with an insertion hole 18c into which the drive shaft 23 and a back spring 36 mounted on the outer periphery of the drive shaft 23 are loosely inserted. A cylindrical insulating cylinder portion 18d extending toward the shaft flange portion 25 and surrounding the outer circumferences of the drive shaft 23 and the back spring 36 is formed. The top portion of the insulating cylindrical portion 18d may extend in the axial direction of the drive shaft beyond the height of the fixed contact.

Here, as shown in FIG. 2, the external dimension of the driving shaft flange portion 25 that contacts the lower center portion of the movable contactor 15 is L1, and the insulating cylindrical portion protruding from the insertion hole 18c of the insulating bottom portion 18b of the insulating holder 18 is L1. Assuming that the outer dimension of the drive shaft 18d is L2, the outer dimension L1 of the drive shaft flange portion 25 is set larger than the outer dimension L2 of the insulating cylinder portion 18d (L1>L2).

Next, operation of the electromagnetic contactor 1 of the first embodiment will be described.
Assume now that the excitation coil 34 of the electromagnet unit 5 is in a non-excited state and the electromagnet unit 5 is in a released state in which no exciting force is generated to move the movable plunger 22 downward.
In this released state, the movable plunger 22 is urged upward away from the upper magnetic yoke 21 by the return spring 36 . At the same time, the attraction force due to the magnetic force of the driving permanent magnet 37 acts on the auxiliary yoke 39, and the peripheral flange 22a of the movable plunger 22 is attracted. Therefore, the upper surface of the peripheral collar portion 22 a of the movable plunger 22 is in contact with the lower surface of the auxiliary yoke 39 .

Therefore, the first movable contact 15 a and the second movable contact 15 b of the movable contact 15 of the contact mechanism 4 connected to the movable plunger 22 via the drive shaft 23 are connected to the first fixed contact of the first fixed contact 13 . 13a is spaced apart from the second fixed contact 14a of the second fixed contact 14; Therefore, the current path between the first fixed contact 13 and the second fixed contact 14 is cut off, and the contact mechanism 4 is opened.
When the contact mechanism 4 is in the open state and the excitation coil 34 of the electromagnet unit 5 is energized, an excitation force is generated in the electromagnet unit 5 to move the movable plunger 22 to the biasing force of the return spring 36 and the attraction of the driving permanent magnet 37 . Push down against force. The descent of the movable plunger 22 is stopped when the lower surface of the peripheral collar portion 22a hits the upper surface of the upper magnetic yoke 21. As shown in FIG.

As the movable plunger 22 descends in this way, the movable contact 15 connected to the movable plunger 22 via the drive shaft 23 also descends, and the first movable contacts 15a, 15 of the movable contact 15 of the contact mechanism 4 move downward. The second movable contact 15 b contacts the first fixed contact 13 a of the first fixed contact 13 and the second fixed contact 14 a of the second fixed contact 14 by the contact pressure of the contact spring 26 .
Therefore, a large current from the power supply source is supplied to the load device through the first fixed contact 13, the movable contact 15, and the second fixed contact 14, resulting in a closed state.
When the current supply to the load device is cut off from the closed state of the contact mechanism 4, the excitation of the exciting coil 34 of the electromagnet unit 5 is stopped.
When the excitation of the excitation coil 34 is stopped, the excitation force for moving the movable plunger 22 downward by the electromagnet unit 5 disappears, so that the movable plunger 22 rises due to the urging force of the return spring 36, and the peripheral flange 22a becomes the auxiliary yoke. The attractive force of the driving permanent magnet 37 increases as it approaches 39 .

As the movable plunger 22 rises, the movable contactor 15 connected via the drive shaft 23 rises. When the contact pressure is applied by the contact spring 26 accordingly, the first movable contact 15a and the second movable contact 15b of the movable contact 15 are connected to the first fixed contact 13a and the second fixed contact 13a of the first fixed contact 13. It is in contact with the second fixed contact 14a of the contactor 14 . After that, when the lower surface of the central portion of the movable contact 15 abuts against the drive shaft flange portion 25 of the rising drive shaft 23 , the movable contact 15 contacts the first fixed contact 13 and the second fixed contact 14 . It becomes an open state (released state) in which it is spaced upward.

When such a contact mechanism 4 repeats the open state and the closed state, the first movable contact 15a and the second movable contact 15b of the movable contact 15, the first fixed contact 13a of the first fixed contact 13, the second 2 When the second fixed contact 14a of the fixed contact 14 contacts and separates, the lower center portion of the movable contact 15 contacts the drive shaft flange portion 25 of the drive shaft 23 to generate metal powder, and the generated metal The powder moves from the outer peripheral portion of the drive shaft flange portion 25 to the insulating bottom portion 18 b side of the insulating holder 18 .
At this time, since the outer dimension L1 of the driving shaft flange portion 25 is set larger than the outer dimension L2 of the insulating cylindrical portion 18d (L1>L2), the outer peripheral edge portion of the driving shaft flange portion 25 is separated from the insulating bottom portion of the insulating holder 18. The metal powder that has moved to the 18b side does not enter through the insertion hole 18c of the insulating cylindrical portion 18d.

Therefore, the metal powder that has moved to the insulating bottom portion 18b does not adhere to the upper surface of the peripheral flange portion 22a of the movable plunger 22, so that the first movable contact 15a and the second movable contact 15a of the movable contactor 15 when the contact mechanism 4 is in the open state. The distance between the movable contact 15b, the first fixed contact 13a of the first fixed contact 13, and the second fixed contact 14a of the second fixed contact 14 is set to sufficiently extinguish the arc generated between the movable contact and the fixed contact. Can be set to an arcable distance. Moreover, since the contact action between the movable plunger 22 and the auxiliary yoke 39 is not hindered, a stable magnetic circuit can be ensured. Furthermore, since foreign matter does not enter the clearance between the movable plunger 22 and the cap 35, a stable sliding operation can be obtained.

Therefore, in the first embodiment, the outer dimension L1 of the drive shaft flange portion 25 is set larger than the outer dimension L2 of the insulating cylindrical portion 18d, so that the lower center portion of the movable contactor 15 is the drive shaft of the drive shaft 23. Metal powder generated by contact with the flange portion 25 is prevented from entering the peripheral flange portion 22a side of the movable plunger 22 through the insertion hole 18c of the insulating holder 18. The distance between the contacts does not become shorter than the standard dimension, and the arc breaking performance generated between the fixed contact and the movable contact is not affected. Moreover, it does not intervene in the contact surface between the movable plunger 22 and the auxiliary yoke 39, and does not affect the operation. Furthermore, since it does not enter the sliding surface of the movable plunger, it does not affect the sliding motion.

[Second embodiment]
Next, FIG. 3 shows the contact mechanism 4 of the electromagnetic contactor 1 of the second embodiment according to the present invention.
The movable contactor 15 of this embodiment is a conductive plate formed of a conductive material elongated in the horizontal direction of FIG. A pair of downward extending portions 15d and 15e extending obliquely downward from both longitudinal ends of 15c, and extending parallel to the central portion 15c from both ends of the pair of downward extending portions 15d and 15e. It has a pair of contact portions 15f and 15g, and a first movable contact 15a and a second movable contact 15b formed on the lower surfaces of the pair of contact portions 15f and 15g.

The insulating bottom portion 18b of the insulating holder 18 of this embodiment is formed with an insertion hole 18c into which the drive shaft 23 and the back spring 36 mounted on the outer periphery of the drive shaft 23 are loosely inserted. A cylindrical insulating cylinder portion 18e is formed extending from the upper opening peripheral edge of the drive shaft 23 toward the drive shaft flange portion 25 of the drive shaft 23 and extending longer than the insulating cylinder portion 18d of the first embodiment.
Assuming that the outer dimension of the insulating cylindrical portion 18e of the insulating holder 18 is L2, and the outer dimension of the drive shaft flange portion 25 that contacts the lower portion of the central portion 15c of the movable contactor 15 is L1, the same as in the first embodiment, The outer dimension L1 of the drive shaft flange portion 25 is set larger than the outer dimension L2 of the insulating cylinder portion 18e (L1>L2).
In addition, the top portion of the insulating cylindrical portion 18e extends in the axial direction of the drive shaft 23 from the height of the fixed contacts 15a and 15b. The top position of the insulating cylindrical portion 18e is set at the same position as the height position of the first movable contact 15a (second movable contact 15b).

Next, operation of the contact mechanism 4 of the second embodiment will be described. A positive (+) terminal is connected to the first fixed contact 13 (conductor portion 11), and a negative (-) terminal is connected to the second fixed contact 14 (conductor portion 12).
When the contact mechanism 4 of the second embodiment repeats the open state and the closed state, the first movable contact 15a and the second movable contact 15b of the movable contact 15 and the first fixed contact 13a of the first fixed contact 13 When the second fixed contact 14a of the second fixed contact 14 contacts and separates, the lower portion of the central portion 15c of the movable contact 15 comes into contact with the drive shaft flange portion 25 of the drive shaft 23, thereby generating metal powder. , the generated metal powder moves from the outer peripheral edge portion of the drive shaft flange portion 25 to the insulating bottom portion 18 b side of the insulating holder 18 .

At this time, since the outer dimension L1 of the driving shaft flange portion 25 is set to be larger than the outer dimension L2 of the insulating cylindrical portion 18e (L1>L2), the distance from the outer peripheral edge portion of the driving shaft flange portion 25 to the insulating bottom portion of the insulating holder 18 is increased. The metal powder that has moved to the 18b side does not enter through the insertion hole 18c of the insulating cylindrical portion 18e.
Therefore, the metal powder that has moved toward the insulating bottom portion 18b does not adhere to the upper surface of the peripheral flange portion 22a of the movable plunger 22. Therefore, when the contact mechanism 4 is in the open state, the first movable contact 15a and the second movable contact 15a of the movable contactor 15 are separated from each other. 2. The distance between the contacts of the movable contact 15b, the first fixed contact 13a of the first fixed contact 13, and the second fixed contact 14a of the second fixed contact 14 is set sufficiently to prevent an arc generated between the movable contact and the fixed contact. Can be set to a distance that can be extinguished. Moreover, it does not intervene in the contact surface between the movable plunger 22 and the auxiliary yoke 39, and does not affect the operation. Furthermore, since it does not enter the sliding surface of the movable plunger, it does not affect the sliding motion.

Also, when the large current of the power supply source is switched from the closed state supplied to the load device through the first fixed contact 13, the movable contact 15, and the second fixed contact 14 to the open state, the movable contact 15 A first arc A1 is generated between the first movable contact 15a of the first fixed contact 13 and the first fixed contact 13a of the first fixed contact 13, and the second movable contact 15b of the movable contact 15 and the second fixed contact 14 of the second fixed contact 14 A second arc A2 is generated between the first fixed contact 14a and these arcs keep the current flowing. At this time, the current direction of the first arc A1 is from the first fixed contact 13a to the first movable contact 15a, and the current direction of the second arc A2 is from the second movable contact 15b to the second fixed contact 14a. It is the direction to go.

The arc A1 generated between the first fixed contact 13a of the first fixed contact 13 and the first movable contact 15a of the movable contact 15 has an arc current flowing from the first fixed contact 13a to the first movable contact 15a. Since the flow direction and the flow direction of the current in the second conductive plate portion 13c of the first fixed contact 13 are opposite to each other, the Lorentzian current flowing toward the inside (right side in FIG. 3) in the longitudinal direction of the movable contact 15 due to the self-magnetic field. A force F1 is generated.
Also, the arc A2 generated between the first fixed contact 14a of the second fixed contact 14 and the second movable contact 15b of the movable contact 15 includes an arc directed from the second movable contact 15b to the second fixed contact 14a. Since the current flow direction and the current flow direction of the second conductive plate portion 14c of the second fixed contactor 14 are opposite to each other, the self-magnetic field moves the movable contactor 15 longitudinally inward (to the left in FIG. 3). A Lorentz force F2 is generated.

Due to the generation of these Lorentz forces F1 and F2, the arcs A1 and A2 generated between the fixed contacts 13a and 14a of the pair of fixed contacts 13 and 14 and the pair of movable contacts 15a and 15b of the movable contact 14 are It moves inward in the longitudinal direction of the movable contactor 15 .
An insulating cylindrical portion 18e of an insulating holder 18 is arranged so as to surround the drive shaft 23 and the back spring 36 inside in the longitudinal direction of the movable contactor 15 where the arcs A1 and A2 move. The top portion of the insulating cylindrical portion 18e extends to the same height position as the first movable contact 15a (second movable contact 15b).

Therefore, when the arcs A1 and A2 come into contact with the insulating cylindrical portion 18e, cooling gas is generated from the insulating cylindrical portion 18e, extinguishing the arcs A1 and A2, and the arc short circuit between the drive shaft 23 and the back spring 36 is caused. prevented.
Therefore, in the contact mechanism 4 of the second embodiment, the arcs A1 and A2 generated between the fixed contacts 13a and 14a of the pair of fixed contacts 13 and 14 and the pair of movable contacts 15a and 15b of the movable contact 14 are movable. Even if the contactor 15 moves inward in the longitudinal direction, the insulating cylindrical portion 18e rising from the insulating bottom portion 18b of the insulating holder 18 surrounds the drive shaft 23 and the back spring 36. It is possible to prevent the arc short circuit of the spring 36 and improve the breaking performance.

Further, in the contact mechanism 4 of the second embodiment, the outer dimension L1 of the drive shaft flange portion 25 is set larger than the outer dimension L2 of the insulating cylindrical portion 18e, so that the lower portion of the center portion of the movable contactor 15 is located on the drive shaft. Metal powder generated by contact with the drive shaft flange portion 25 of 23 is prevented from entering the peripheral flange portion 22a side of the movable plunger 22 through the insertion hole 18c of the insulating holder 18, thereby fixing the open state. The inter-contact distance between the contact and the movable contact does not become shorter than the reference dimension, and the arc breaking performance generated between the fixed contact and the movable contact is not affected. Moreover, it does not intervene in the contact surface between the movable plunger 22 and the auxiliary yoke 39, and does not affect the operation. Furthermore, since it does not enter the sliding surface of the movable plunger, it does not affect the sliding motion.

1 Electromagnetic Contactor 2 Case Body 3 Case Lid 4 Contact Mechanism 5 Electromagnet Unit 6 Contact Storage Case 7 Rectangular Tube 7a Rectangular Tube Flange 8 Insulating Substrates 9, 10 Through Holes 11, 12 Conductor 13 First Fixed Contact 13a First fixed contact 14 Second fixed contact 14a Second fixed contact 15 Movable contact 15a First movable contact 15b Second movable contact 15c Central portions 15d, 15e Downward extending portion (extending portion)
15f, 15g Contact parts 16, 17 Cover 18 Insulation holder 18a Rectangular cylinder insulation wall 18b Insulation bottom (bottom part)
18c insertion hole 18e insulating cylindrical portion 21 upper magnetic yoke 21a through hole 22 movable plunger 22a peripheral collar portion 23 drive shaft 24 through hole 25 drive shaft flange portion 26 contact spring 27a spring receiver 27b C ring 28 magnetic yoke 29 fixed plunger 30 spool 31 Central cylindrical portion 32 Lower flange portion 33 Upper flange portion 34 Exciting coil 35 Cap 35a Flange portion 36 Back spring 37 Driving permanent magnet 38 Through hole 39 Auxiliary yoke

Claims (3)

A contact mechanism comprising a pair of fixed contacts having fixed contacts and a movable contact provided with a pair of movable contacts capable of contacting and separating from the fixed contacts on both ends in the longitudinal direction;
an electromagnet unit having a drive shaft connected to the movable contact and driving the movable contact in a contacting/separating direction with respect to the pair of fixed contacts;
a contact housing case housing the contact mechanism and the drive shaft;
an insulating holder, which is a cylindrical member with a bottom and has an insertion hole formed in a bottom portion through which the drive shaft is inserted, and is arranged in the contact housing case;
The drive shaft has a drive shaft flange portion protruding from the outer circumference of the drive shaft,
The movable contactor is slidably supported on the drive shaft with its center portion pressed against the drive shaft flange portion by a contact spring,
A cylindrical insulating tube portion rising from the opening peripheral edge of the insertion hole and covering the outer periphery of the drive shaft is formed at the bottom of the insulating holder,
An electromagnetic contactor, wherein the outer peripheral dimension of the drive shaft flange portion is set to be larger than the outer peripheral dimension of the insulating cylindrical portion. 2. The magnetic contactor according to claim 1, wherein the top portion of said insulating cylindrical portion extends in the axial direction of said drive shaft at least above the height of said fixed contact. The pair of fixed contacts includes a first conductive plate portion provided with the fixed contact, a second conductive plate portion extending in the contact/separation direction from an end portion of the first conductive plate portion, and the second conductive plate portion. a third conductive plate portion extending from an end of the plate portion, and having a C-shape when viewed from the side;
The movable contact has a central portion connected to the drive shaft and obliquely extends from both ends in the longitudinal direction of the central portion with respect to the contact/separation direction toward the first conductive plate portions of the pair of fixed contacts. and a pair of contact portions provided with the movable contact extending from the ends of the pair of extension portions in a direction facing the first conductive plate portion,
3. The magnetic contactor according to claim 2, wherein the top portion of the insulating cylindrical portion extends close to the central portion of the movable contactor.

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