JP2016062691A - Electromagnetic contactor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electromagnetic contactor which is downsized but has a large counter area between a peripheral collar part of a movable plunger and a yoke face of a magnetic yoke to have great suction force for the movable plunger.SOLUTION: A movable plunger 35 includes a cylindrical plunger body 40, a peripheral collar part 41 formed in one end of the plunger body, and a constriction part 42 formed in one end side near the peripheral collar part of the plunger body with a diameter being smaller than the plunger body.SELECTED DRAWING: Figure 6

Description

  The present invention relates to an electromagnetic contactor that opens and closes a current path.

As an electromagnetic contactor for opening and closing a current path, for example, the one described in Patent Document 1 is known.
The electromagnetic contactor described in Patent Document 1 includes a contact mechanism having a pair of fixed contacts, a movable contact that can be contacted with and separated from the pair of fixed contacts, and an electromagnet unit that drives the contact mechanism. Yes.
The electromagnet unit includes a movable plunger coupled to a movable contact of a contact mechanism by a coupling shaft, an excitation coil that generates a magnetic flux by applying a predetermined voltage to drive the movable plunger, and a magnetic yoke that surrounds the excitation coil. It has.
The magnetic yoke is composed of a lower magnetic yoke having a U-shaped cross section and an upper magnetic yoke bridged in the upper opening of the lower magnetic yoke.

The movable plunger is provided with a cylindrical plunger body whose connecting shaft is coaxially connected, and a peripheral flange portion formed at the other end of the plunger body, and the plunger body is inserted into a plunger through hole formed in the upper magnetic yoke. The peripheral flange portion is opposed to the upper surface of the upper magnetic yoke around the plunger through hole.
An annular permanent magnet that is magnetized in the movable direction of the movable plunger is fixed so as to surround the peripheral flange of the movable plunger, and a return spring is provided that applies a spring force to the movable plunger in a direction away from the upper magnetic yoke. The gap between the peripheral flange portion and the upper magnetic yoke in the released state is set to g1 by the peripheral flange portion coming into contact with the auxiliary yoke fixed to the permanent magnet.

When the exciting coil is energized, a magnetic flux is generated in the gap g1, thereby generating an attractive force that abuts the peripheral flange portion against the upper magnetic yoke against the attractive force of the permanent magnet and the spring force of the return spring. Since the pair of fixed contacts and movable contacts of the mechanism come into contact, a current path is formed and the input state is established.
Here, the gap g2 between the inner peripheral surface of the plunger through hole of the upper magnetic yoke through which the plunger main body of the movable plunger is inserted and the outer peripheral surface of the plunger main body is larger than the gap g1 between the peripheral flange portion and the upper magnetic yoke. Is set to a value (g2> g1).

JP 2012-243583 A

By the way, in the electromagnetic contactor of Patent Document 1 described above, the plunger main body of a movable plunger having the same outer diameter dimension is inserted through the plunger through hole of the upper magnetic yoke from one end to the other end in the axial direction. In order to provide a gap g2 larger than the gap g1 between the outer peripheral surface of the plunger main body and the inner peripheral surface of the plunger through hole, it is conceivable to form a plunger through hole having a large hole diameter in the upper magnetic yoke.
If a plunger through-hole with a large hole diameter is formed in the upper magnetic yoke in this way, the facing area between the peripheral flange portion of the movable plunger and the upper magnetic yoke is reduced, and even if the excitation coil is excited, the attractive force to the movable plunger is increased. It cannot be generated sufficiently.

Therefore, in order to set a large facing area between the peripheral flange portion of the movable plunger and the yoke surface of the upper magnetic yoke, it is conceivable to increase the outer peripheral shape of the peripheral flange portion. There is a problem in terms of downsizing.
The present invention has been made to solve the above-described problem, and increases the attractive force to the movable plunger by increasing the facing area of the peripheral flange portion and the upper magnetic yoke of the movable plunger while reducing the size. It is an object of the present invention to provide an electromagnetic contactor capable of performing the above.

  In order to achieve the above object, an electromagnetic contactor according to an aspect of the present invention includes a pair of fixed contacts, a contact mechanism having a movable contact that can contact and separate from the pair of fixed contacts, and the contact mechanism. The electromagnet unit includes a movable plunger coupled to the movable contact, an excitation coil for generating a magnetic flux for driving the movable plunger, and a magnetic yoke surrounding the excitation coil. I have. The magnetic yoke is composed of a lower magnetic yoke having a U-shaped cross section and an upper magnetic yoke that bridges the upper opening of the lower magnetic yoke. The movable plunger is formed by reducing the diameter of the plunger main body, a peripheral flange formed at one end of the plunger main body, and a diameter of the plunger main body at one end close to the peripheral flange. And a constricted portion facing the plunger through hole formed in the upper magnetic yoke.

  According to the electromagnetic contactor according to the present invention, the diameter of the plunger through hole of the magnetic yoke is reduced by forming the constricted portion formed by reducing the diameter of the plunger body on one end side close to the peripheral flange portion of the plunger body. In addition, the facing area between the peripheral flange portion of the movable plunger and the upper magnetic yoke can be set large. Thereby, the magnetic resistance in the gap between the peripheral flange portion and the upper surface of the upper magnetic yoke can be reduced, and the attractive force with respect to the movable plunger can be sufficiently increased. Moreover, since it is not necessary to form a large outer peripheral shape of the peripheral flange portion in order to set a large facing area between the peripheral flange portion of the movable plunger and the upper magnetic yoke, it is possible to reduce the size of the electromagnetic contactor.

It is sectional drawing which shows the electromagnetic contactor which concerns on 1st Embodiment of this invention. In the electromagnetic contactor of 1st Embodiment, it is a perspective view which decomposes | disassembles and shows a storage chamber, a fixed plunger, a spool, the exciting coil wound by the spool, and the lower magnetic yoke. It is a disassembled perspective view of the electromagnetic contactor of 1st Embodiment. It is a perspective view which shows the movable plunger of 1st Embodiment. It is a half sectional view of the electromagnet unit which constitutes the electromagnetic contactor of a 1st embodiment. It is a figure which shows a closed magnetic circuit when the exciting coil of the electromagnet unit of 1st Embodiment has excited.

Embodiments of the present invention will be described below with reference to the drawings.
The electromagnetic contactor according to the first embodiment of the present invention is shown in FIGS. 1 to 6. The electromagnetic contactor 1 includes a contact mechanism 2, an electromagnet unit 3 that drives the contact mechanism 2, and a contact mechanism 2. And a sealed housing chamber 4 for housing a connecting shaft 37 and a movable plunger 35, which will be described later.
The contact mechanism 2 is housed in a contact mechanism housing case 5 that constitutes the housing chamber 4, and the contact mechanism housing case 5 closes a metallic rectangular tube 6 and the upper end of the rectangular tube 6. And a flat ceramic insulating substrate 7. The rectangular cylindrical body 6 has a flange portion 6 a that protrudes outward at a lower end portion, and the flange portion 6 a is sealed and joined to the upper surface of an upper magnetic yoke 8 that constitutes the storage chamber 4. A pair of through holes 7a and 7b are formed in the insulating substrate 7 at a predetermined interval. A metallization process is performed on the periphery of the through holes 7 a and 7 b on the upper surface of the insulating substrate 7 and the position where the rectangular tube 6 contacts on the lower surface of the insulating substrate 7.

  The contact mechanism 2 includes a pair of fixed contacts 23 and 24 (hereinafter referred to as a first conductor portion 21 and a second conductor portion 22) fixed to the insulating substrate 7 via a pair of conductor portions 21 and 22 (hereinafter referred to as a first conductor portion 21 and a second conductor portion 22). And the first fixed contact 23 and the second fixed contact 24), and the movable contact 25 arranged so as to be able to contact with and separate from the first fixed contact 23 and the second fixed contact 24. I have. The first conductor portion 21 is inserted and fixed in the through hole 7a of the insulating substrate 7, and the second conductor portion 22 is inserted and fixed in the through hole 7b of the insulating substrate 7.

  The first fixed contact 23 is a C-shaped conductive plate made of copper or the like in a side view, and includes an upper plate portion 23a extending outward along the lower surface of the insulating substrate 7, and an outer end portion of the upper plate portion 23a. An intermediate plate portion 23b extending downward and a lower plate portion 23c extending inward from the lower end portion of the intermediate plate portion 23b in parallel with the upper plate portion 23a are provided. The lower plate portion 23c includes a first contact 23d that extends below the movable contact 25 and contacts the first contact of the movable contact 25 on the upper surface thereof.

  On the other hand, the second fixed contact 24 is also a C-shaped conductive plate made of copper or the like in a side view, like the first fixed contact 23, and extends upward along the lower surface of the insulating substrate 7. 24a, an intermediate plate portion 24b extending downward from the outer end portion of the upper plate portion 24a, and a lower plate portion 24c extending inward from the lower end portion of the intermediate plate portion 24b in parallel with the upper plate portion 24a. . The lower plate portion 24c includes a second contact 24d that extends below the movable contact 25 and contacts the second contact of the movable contact 25 on the upper surface thereof.

Each of the first fixed contact 23 and the second fixed contact 24 is fixed to the first conductor portion 21 and the second conductor portion 22, respectively. As a fixing method thereof, brazing, screwing, or the like can be given. It is done.
A C-shaped magnetic material plate 28 is mounted so as to cover the inner surface of the intermediate plate portion 23b of the first fixed contact 23 and the inner surface of the intermediate plate portion 24b of the second fixed contact 24 as viewed from above. Yes. Thereby, the magnetic field generated by the current flowing through the intermediate plate portions 23b and 24b can be shielded.

  A synthetic resin insulating cover 26 that restricts the generation of arc is attached to the first fixed contact 23, and a synthetic resin insulating cover 27 that restricts the occurrence of arc is also attached to the second fixed contact 24. Has been. As a result, only the first contact 23 d on the upper surface side of the lower plate portion 23 c is exposed on the inner peripheral surface of the first fixed contact 23. Further, only the second contact 24 d on the upper surface side of the lower plate portion 24 c is exposed on the inner peripheral surface of the second fixed contact 24.

  The movable contact 25 is a conductive plate that is long in the left-right direction in FIG. 1 and made of copper or the like as a material. The movable contact 25 is disposed so that both ends are disposed in the first fixed contact 23 and the second fixed contact 24. Has been. The movable contact 25 is supported by a connecting shaft 37 fixed to a movable plunger 35 described later of the electromagnet unit 3. A through hole through which the connecting shaft 37 is inserted is formed at the center of the movable contact 25.

  A flange portion 37 a is formed to protrude outward at a substantially central portion in the vertical direction of the connecting shaft 37. The movable contact 25 is placed on the flange portion 37 a through the through hole from above the connecting shaft 37. Then, the contact spring 39 is inserted from above the connecting shaft 37, the fixing member 38 is inserted from above the connecting shaft 37 to the connecting shaft 37, and the upper end of the contact spring 39 is adjusted so as to obtain a predetermined urging force by the contact spring 39. It is stopped by the fixing member 38.

  The movable contact 25 is in a released state, and the first contact and the second contact at both ends are spaced apart from the first contact 23d of the first fixed contact 23 and the second contact 24d of the second fixed contact 24, respectively. Is kept apart. Further, the movable contact 25 is in the closing position, and the first contact and the second contact at both ends are respectively connected to the first contact 23d of the first fixed contact 23 and the second contact 24d of the second fixed contact 24, respectively. The contact spring 39 is set to contact at a predetermined contact pressure.

As shown in FIG. 1, an insulating cylinder portion 14 formed in a bottomed rectangular cylinder shape is disposed on the inner peripheral surface of the rectangular cylinder body 6 of the contact mechanism accommodation case 5. The insulating cylinder portion 14 has an insulating function to block the influence of the arc on the metal square cylinder body 6.
As shown in FIGS. 1 to 3, the electromagnet unit 3 has a U-shaped lower magnetic yoke 31 as viewed from the side, and a fixed plunger 32 is disposed at the center of the bottom plate portion of the lower magnetic yoke 31. Yes. A spool 33 is disposed outside the fixed plunger 32.

  As shown in FIG. 1, the spool 33 includes a central cylindrical portion 33a through which the fixed plunger 32 is inserted, a lower flange portion 33b projecting radially outward from a lower end portion of the central cylindrical portion 33a, and an upper end portion of the central cylindrical portion 33a. And an upper flange portion 33c protruding outward in the radial direction. As shown in FIGS. 1 to 3, an exciting coil 34 is wound around a storage space formed by a central cylindrical portion 33a, a lower flange portion 33b, and an upper flange portion 33c of the spool 33.

A plate-like upper magnetic yoke 8 is fixed to the upper end serving as the open end of the lower magnetic yoke 31. A plunger through hole 8 a is formed at the center of the upper magnetic yoke 8.
A concave portion 32a is formed in the upper portion of the fixed plunger 32 disposed in the central cylindrical portion 33a of the spool 33, and a cap 9 formed in a bottomed cylindrical shape is disposed in the concave portion 32a. Thereby, the rising portion 32 b of the fixed plunger 32 rising from the peripheral edge of the recess 32 a surrounds the peripheral surface of the cap 9.

A flange portion 9 a protruding outward in the radial direction provided at the open end of the cap 9 is sealed and bonded to the lower surface of the upper magnetic yoke 8. Thus, a sealed container (accommodating chamber 4) is formed in which the contact mechanism accommodating case 5 and the cap 9 are communicated with each other via the plunger through hole 8a of the upper magnetic yoke 8.
Inside the cap 9, a movable plunger 35 having a return spring 36 disposed at the bottom is accommodated so as to be movable in the vertical direction.

  As shown in FIGS. 1, 4 and 5, the movable plunger 35 has a cylindrical plunger main body 40 accommodated in the cap 9 so as to be movable in the vertical direction, and an outer diameter larger than the plunger through hole 8a. A peripheral flange portion 41 located above the upper magnetic yoke 8, and a constricted portion 42 formed between the plunger main body 40 and the peripheral flange portion 41 and having a smaller outer diameter than the plunger main body 40. The constricted part 42 is located inside the plunger through hole 8a of the upper magnetic yoke 8.

Here, as shown in FIG. 5, in a state where the peripheral flange portion 41 of the movable plunger 35 is in contact with the auxiliary yoke 12 (a released state described later), the upper end portion of the constricted portion 42 on the peripheral flange portion 41 side and the plunger main body. The lower end portion on the 40 side is separated from the inner peripheral surface of the plunger through hole 8a.
On the axis of the movable plunger 35, a fitting hole 43 into which the connecting shaft 37 is fitted and a spring housing hole 44 in which the return spring 36 is arranged are formed on the upper end side on the peripheral flange 41 side.

As shown in FIG. 5, the cross-sectional area of the constricted portion 42 (the cross-sectional area between the outer peripheral surface of the constricted portion 42 and the inner peripheral surface of the fitting hole 43) is S <b> 1, and the plunger main body 40 provided with the spring accommodating hole 44. When the cross-sectional area at the lower end (the cross-sectional area between the outer peripheral surface of the plunger main body 40 and the inner peripheral surface of the spring housing hole 44) is S2, the relationship of S1 ≧ S2 is set.
In addition, the site | part with the smallest radial direction cross-sectional area of the plunger main body which concerns on this invention respond | corresponds to the lower end part of the plunger main body 40 in which the spring accommodating hole 44 was provided.

As shown in FIGS. 1 and 5, the upper magnet yoke 8 has an upper surface 8 b on the upper surface 8 b of which the permanent magnet 11 having a square outer shape and a circular center opening is formed in an annular shape. 41 is fixed so as to surround it. The permanent magnet 11 is magnetized in the vertical direction, that is, in the thickness direction so that the upper end side is, for example, the N pole and the lower end side is the S pole.
On the upper surface of the permanent magnet 11, an auxiliary yoke 12 having the same outer shape as the permanent magnet 11 and having a through hole 12 a having an inner diameter smaller than that of the peripheral flange portion 41 of the movable plunger 35 is fixed.
An elastic plate-like foreign matter intrusion preventing member 13 is fixed to the upper surface of the auxiliary yoke 12.
A connecting shaft 37 that is inserted into the insertion hole 43 of the movable plunger 35 passes through the through hole 12 a of the auxiliary yoke 12 and the through hole 13 a of the foreign matter intrusion prevention member 13.

In the released state of the electromagnetic contactor according to the first embodiment, the movable plunger 35 is urged upward by the return spring 36, so that the upper surface of the peripheral flange portion 41 is in the released position where it contacts the lower surface of the auxiliary yoke 12. In this state, the pair of contacts of the movable contact 25 are spaced apart from the contacts 23d and 24d of the first fixed contact 23 and the second fixed contact 24, and the current is cut off.
In this released state, the peripheral flange portion 41 of the movable plunger 35 is attracted to the auxiliary yoke 12 by the magnetic force of the permanent magnet 11, and the movable plunger 35 is inadvertently caused by external vibration, impact, etc. coupled with the urging force of the return spring 36. A state of contacting the auxiliary yoke 12 without moving downward is ensured.

In the released state, as shown in FIG. 6, the gap G <b> 1 between the lower surface of the peripheral flange portion 41 of the movable plunger 35 and the upper surface 8 b of the upper magnetic yoke 8, the outer peripheral surface of the constricted portion 42 of the movable plunger 35, and the upper magnetic field. The relationship between the inner peripheral surface of the plunger through-hole 8a of the yoke 8 and the gap G2 is set such that the gap G2 is larger than the gap G1 (G1 <G2).
When the exciting coil 34 is energized in the released state, it passes from the movable plunger 35 through the peripheral flange 41, passes through the gap G1 between the peripheral flange 41 and the upper magnetic yoke 8, and reaches the upper magnetic yoke 8. A closed magnetic path is formed from the magnetic yoke 8 through the U-shaped lower magnetic yoke 31 to the plunger main body 40 and the constricted portion 42 of the movable plunger 35 through the rising portion 32b at the periphery of the concave portion 32a of the fixed plunger 32.

Thereby, the magnetic flux density of the gap G1 between the lower surface of the peripheral flange portion 41 of the movable plunger 35 and the upper surface 8b of the upper magnetic yoke 8 is increased, and a large attractive force is generated to cause the movable plunger 35 to be biased by the return spring 36. And it is lowered against the attractive force of the permanent magnet 11.
Accordingly, the pair of movable contacts of the movable contact 25 connected to the movable plunger 35 via the connecting shaft 37 is brought into contact with the contacts 23d and 24d of the first fixed contact 23 and the second fixed contact 24, A current path from the first fixed contact 23 to the second fixed contact 24 through the movable contact 25 is formed and the input state is established.

The upper magnetic yoke 8 is joined to the upper surface of the upper magnetic yoke 8, and the contact mechanism housing case 5 for housing the contact mechanism 2 therein, and the lower magnetic yoke 8 is joined to the lower surface of the upper magnetic yoke 8, and the movable plunger 35 is housed therein. The cap 9 that is configured constitutes a sealed housing chamber 4 that houses the contact mechanism 2, the connecting shaft 37, and the movable plunger 35. A gas such as hydrogen gas, nitrogen gas, a mixed gas of hydrogen and nitrogen, air, or SF ₆ is sealed in the sealed storage chamber 4.

Next, operation | movement of the electromagnetic contactor 1 of 1st Embodiment is demonstrated.
Now, it is assumed that the first fixed contact 23 is connected to a power supply source that supplies a large current, for example, and the second fixed contact 24 is connected to a load.
In this state, it is assumed that the exciting coil 34 of the electromagnet unit 3 is in a non-excited state, and the electromagnet unit 3 is in a released state in which no attracting force for lowering the movable plunger 35 is generated. In this released state, the movable plunger 35 is urged upward by the return spring 36 away from the upper magnetic yoke 8.

At the same time, the attractive force due to the magnetic force of the permanent magnet 11 is applied to the auxiliary yoke 12, and the peripheral flange portion 41 of the movable plunger 35 is attracted. Therefore, the upper surface of the peripheral flange portion 41 of the movable plunger 35 is in contact with the lower surface of the auxiliary yoke 12.
Therefore, the contact of the movable contact 25 of the contact mechanism 2 connected to the movable plunger 35 via the connection shaft 37 is connected to the first and second contacts 23d and 24d of the first and second fixed contacts 23 and 24. It is spaced upward by a predetermined distance. For this reason, the current path between the first and second stationary contacts 23 and 24 is in a disconnected state, and the contact mechanism 2 is in an open state.

  When the exciting coil 34 of the electromagnet unit 3 is excited from this released state, the movable plunger 35 passes through the peripheral flange 41 and passes through the gap G1 between the peripheral flange 41 and the upper magnetic yoke 8 to the upper magnetic yoke 8. A closed magnetic path is reached from the upper magnetic yoke 8 through the U-shaped lower magnetic yoke 31, through the rising portion 32 b at the periphery of the concave portion 32 a of the fixed plunger 32, and to the plunger main body 40 and the constricted portion 42 of the movable plunger 35. It is formed.

Due to the attractive force generated by the excitation of the exciting coil 34, the movable plunger 35 is pushed downward against the urging force of the return spring 36 and the attractive force of the annular permanent magnet 11.
At this time, as shown in FIG. 6, compared to the gap G <b> 2 between the outer peripheral surface of the constricted portion 42 of the movable plunger 35 and the inner peripheral surface of the plunger through hole 8 a of the upper magnetic yoke 8, A gap G1 between the lower surface of the peripheral flange portion 41 and the upper surface 8b of the upper magnetic yoke 8 is set small.

Further, in the released state where the peripheral flange portion 41 of the movable plunger 35 is in contact with the auxiliary yoke 12, the upper end 42a of the constricted portion 42 on the peripheral flange portion 41 side is in the axial direction with respect to the inner peripheral surface of the plunger through hole 8a. Since the lower end 42b on the peripheral flange 41 side of the constricted portion 42 is located axially downward with respect to the inner peripheral surface of the plunger through hole 8a, the upper magnetic yoke extends from the outer peripheral surface of the constricted portion 42 to the upper magnetic yoke. Magnetic flux toward the plunger through hole 8a is hardly generated.
Thus, in the released state, the constricted portion 42 of the movable plunger 35 faces the plunger through hole 8a of the upper magnetic yoke 8, so that the lower surface of the peripheral flange portion 41 of the movable plunger 35 and the upper surface 8b of the upper magnetic yoke 8 are provided. The magnetic flux density between is increased.

  Further, in the closed magnetic circuit that reaches the plunger main body 40, the constricted portion 42, and the peripheral flange portion 41 of the movable plunger 35 through the rising portion 32b at the peripheral edge of the concave portion 32a of the fixed plunger 32 by the excitation of the exciting coil 34 described above in FIG. As shown, the cross-sectional area S1 of the constricted portion 42 is equal to the cross-sectional area S2 of the lower portion of the plunger main body 30 in which the spring housing hole 44 is formed, which is the portion having the smallest radial cross-sectional area of the plunger main body 30, or A value larger than the cross-sectional area S2 (S1 ≧ S2) is set. Thereby, the magnetic flux flow from the plunger main body 30 of the movable plunger 35 to the peripheral flange portion 41 becomes smooth.

As a result, the movable plunger 35 quickly descends against the spring force of the return spring 36 and the attractive force of the permanent magnet 11. Then, the lowering of the movable plunger 35 is stopped when the lower surface of the peripheral flange portion 41 comes into contact with the upper surface 8 a of the upper magnetic yoke 8. Thus, when the movable plunger 35 is lowered, the movable contact 25 connected to the movable plunger 35 via the connecting shaft 37 is also lowered, and the contact of the movable contact 25 is the first and second fixed contacts. The first and second contacts 23d and 24d of 23 and 24 are brought into contact with the contact pressure of the contact spring 39.
Therefore, a closed state is reached in which a large current from the external power supply source is supplied to the load through the first fixed contact 23, the movable contact 25, and the second fixed contact 24.

Next, the effect of the electromagnetic contactor 1 of 1st Embodiment is demonstrated.
In the electromagnetic contactor 1 of the first embodiment, the lower surface of the peripheral flange portion 41 of the movable plunger 35 and the upper surface 8b of the upper magnetic yoke 8 are in a released state where the upper surface of the peripheral flange portion 41 of the movable plunger 35 contacts the auxiliary yoke 12. In order to increase the gap G2 between the outer peripheral surface of the movable plunger 35 and the inner peripheral surface of the plunger through hole 8a of the upper magnetic yoke 8 with respect to the gap G1 between the upper magnetic yoke 8 and the upper magnetic yoke 8 as in the conventional structure. The gap G2 is provided by providing the constricted portion 42 at the position of the movable plunger 35 inserted through the plunger through hole of the upper magnetic yoke 8 without increasing the diameter of the plunger through hole 8a.

  In this way, the gap G2 is provided by forming the constricted portion 42 at a position facing the inner peripheral surface of the plunger through hole 8a, and the diameter of the plunger through hole 8a of the upper magnetic yoke 8 is not increased. The facing area between the peripheral flange 41 and the upper surface 8b of the upper magnetic yoke 8 can be set large. Thereby, the magnetic resistance of the gap G1 between the lower surface of the peripheral flange portion 41 and the upper surface 8b of the upper magnetic yoke 8 can be reduced, and the attractive force with respect to the movable plunger 35 can be sufficiently increased.

Further, since it is not necessary to form a large outer peripheral shape of the peripheral flange portion 41 in order to set a large facing area between the peripheral flange portion 41 of the movable plunger 35 and the upper surface 8b of the upper magnetic yoke 8, the electromagnetic contactor 1 Miniaturization can be achieved.
Further, in the released state, the upper end 42a of the constricted portion 42 on the peripheral flange portion 41 side is positioned above the inner peripheral surface of the plunger through hole 8a in the axial direction, and the lower end 42b of the constricted portion 42 on the peripheral flange portion 41 side. Is located below the inner peripheral surface of the plunger through hole 8a in the axial direction, so that almost no magnetic flux from the outer peripheral surface of the constricted portion 42 toward the plunger through hole 8a of the upper magnetic yoke 8 is generated. The magnetic flux density generated in the gap G1 between the lower surface of the portion 41 and the upper surface 8b of the upper magnetic yoke 8 can be further increased.

  Further, in the closed magnetic path of the movable plunger 35, the upper magnetic yoke 8, the lower magnetic yoke 31, and the fixed plunger 32, which are excited by the excitation coil 34, the cross-sectional area S 1 of the constricted portion 42 is the smallest in the radial direction. The plunger main body 30 of the movable plunger 35 is set to be equal to or larger than the cross-sectional area S2 (S1 ≧ S2) with respect to the cross-sectional area S2 of the lower part of the plunger main body 30 in which the spring housing hole 44 as a part is formed. Thus, the flow of magnetic flux from the peripheral flange portion 41 to the outer periphery 41 becomes smooth, and the attraction force by excitation of the excitation coil 34 that attracts the movable plunger 35 to the upper magnetic yoke 8 can be increased.

The first embodiment of the present invention has been described above, but the present invention is not limited to this, and various changes and improvements can be made.
For example, if the storage chamber 4 has a sealed structure capable of storing the contact mechanism 2 having the pair of fixed contacts 23 and 24 and the movable contact 25, the connecting shaft 37, and the movable plunger 35, the upper magnetic yoke 8; It is not always necessary to configure the contact mechanism housing case 5 and the cap 9.
Moreover, although the movable plunger 35 of 1st Embodiment was demonstrated as what is formed with 1 components, for example, 2 components which consist of a component provided with the constriction part 42 and the plunger main body 40, and a component provided with the surrounding collar part 41. The structure which integrates may be sufficient.

DESCRIPTION OF SYMBOLS 1 Electromagnetic contactor 2 Contact mechanism 3 Electromagnet unit 4 Storage chamber 5 Contact mechanism storage case 6 Square cylinder 6a Flange part 7 Insulating substrate 7a Through hole 7b Through hole 8 Upper magnetic yoke 8a Movable plunger through hole 8b Upper surface 9 of upper magnetic yoke Cap 9a Flange portion 11 Permanent magnet 12 Auxiliary yoke 12a Through hole 13 Foreign matter intrusion prevention member 13a Through hole 14 Insulating tube portion 21 Conductor portion 22 Conductor portion 23 First fixed contact 23a Upper plate portion 23b Intermediate plate portion 23c Lower plate portion 23d First contact 24 Second fixed contact 24a Upper plate 24b Intermediate plate 24c Lower plate 24d Second contact 25 Movable contact 26 Insulation cover 27 Insulation cover 28 Magnetic plate 31 Lower magnetic yoke 32 Fixed plunger 32a Recess 32b Part 33 Spool 33a Central cylindrical part 33b Lower flange part 33c Upper flange part 34 Excitation Magnetic coil 35 Movable plunger 36 Return spring 37 Connecting shaft 37a Flange portion 38 Fixing member 39 Contact spring 40 Plunger body 41 Circumferential flange portion 42 Constricted portion 42a Upper end of the constricted portion (end portion on the peripheral flange portion side)
42b Upper end of the constricted portion (end on the plunger body side)
43 Insertion hole 44 Spring storage hole G1 Gap between the peripheral flange portion of the movable plunger and the yoke surface of the magnetic yoke G2 Gap between the inner peripheral surface of the plunger through hole and the outer peripheral surface of the constriction portion Thickness of the constriction portion T2 Thickness of the lower end of the plunger body

Claims (4)

A contact mechanism having a pair of fixed contacts and a movable contact that can be contacted with and separated from the pair of fixed contacts, and an electromagnet unit that drives the contact mechanism;
The electromagnet unit includes a movable plunger connected to the movable contact, an excitation coil for generating a magnetic flux for driving the movable plunger, and a magnetic yoke surrounding the excitation coil.
The movable plunger is formed by reducing the diameter of the plunger main body, a peripheral flange formed at one end of the plunger main body, and a diameter of the plunger main body at one end close to the peripheral flange of the plunger main body, An electromagnetic contactor comprising: a constricted portion facing a plunger through hole formed in the upper magnetic yoke.   In the released state of the movable plunger, the peripheral flange portion is opposed to the yoke surface of the magnetic yoke around the plunger through hole with a gap G1, and the inner peripheral surface of the plunger through hole and the outer peripheral surface of the constricted portion 2. The electromagnetic contactor according to claim 1, wherein the movable plunger is arranged with a gap G <b> 2 having a size larger than that of the gap G <b> 1.   The end portion of the constricted portion on the peripheral flange portion side is present at a position shifted in the axial direction with respect to the inner peripheral surface of the plunger through hole, and the end portion of the constricted portion on the plunger main body side is also the plunger. The electromagnetic contactor according to claim 1, wherein the electromagnetic contactor is located at a position shifted in an axial direction with respect to an inner peripheral surface of the through hole. The radial cross-sectional area of the constricted portion is set to be equal to a portion where the plunger main body has the smallest radial cross-sectional area or a value larger than a portion where the radial cross-sectional area is small. The electromagnetic contactor in any one of thru | or 3.

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