JP2003068179A - Sealed contact device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide, with a simple structure and at a low cost, a sealed contact device having a safety mechanism capable of preventing contacts from being shortcircuited even if an operating signal is erroneously inputted into an input side or excessive vibration is applied to the device. SOLUTION: This sealed contact device having the contacts stored in an air-tight space thereof sealingly filled with hydrogen or gas formed mainly of hydrogen comprises a forced locking means for preventing the contacts from being shortcircuited. The forced locking means is formed in a permanent magnet 17 for magnetically stopping the movement of a movable iron core. The permanent magnet 17 is fixed to a rotating member 18 installed so as to be rotated on the inside of a housing 16 and generally in the same plane as the bottom surface of a tubular body 7 (not shown), and the rotating member 18 is rotated from the outside of the housing 16. The forced locking means can also be formed in a magnetic path cutting part for attaching and detaching a part of the yoke of a magnetic circuit for moving the movable iron core by a magnetic force.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sealed contact device suitable for relays for power loads, electromagnetic switches and the like.

[0002]

2. Description of the Related Art Conventionally, as a sealed contact device of this type, for example, as shown in an explanatory view of FIG.
There is a sealed contact device A disclosed as No. 8.

This sealed contact device A is, as will be described later,
Since the relay contact portion is housed in an airtight space in which hydrogen or a gas mainly containing hydrogen is sealed, an arc generated when the contacts are opened does not leak to the outside of the device. Therefore, the sealed contact device A does not require the arc space that was necessary in the air switch, and can be closely attached to increase the mounting density. For example, the sealed contact device A is mounted in a hybrid vehicle, an electric vehicle, or the like. It is suitable for controlling energization / interruption of direct current high voltage / high current of a battery or the like, and is configured as follows.

Reference numeral 2 denotes a sealed container, which is made of a heat-resistant insulating material such as ceramic and is formed in a box shape with one surface opened, and through holes are provided at two locations on the bottom thereof.

Fixed terminals 3 and 3 are made of, for example, a copper-based material, and are formed in a substantially multi-stepped bottomed cylindrical shape, and fixed contacts 3a, 3a are fixed to one end on the bottom side. The fixed terminals 3 and 3 are airtightly joined to the sealing container 2 by brazing or the like with the other ends protruding from the sealing container 2. The fixed contacts 3a, 3a may be provided integrally with the fixed terminals 3, 3.

Reference numeral 4 denotes a movable contact, which is made of, for example, a copper-based material and is formed in a flat plate shape, and is arranged with a space for contacting and separating from the fixed contacts 3a, 3a.

A movable iron core 5 moves so that the movable contact 4 comes into contact with and separates from the fixed contacts 3a, 3a. The movable iron core 5 is formed in a substantially cylindrical shape and has an insertion hole through which a movable shaft 10 described later is inserted. It is provided in the axial direction.

Reference numeral 6 denotes a fixed iron core, one end of which is formed into a thick columnar shape, and an insertion hole through which a movable shaft 10 described later is inserted is provided in the axial direction. This fixed iron core 6 has a first
The one end portion is fixed by being inserted into the insertion hole of the joining member 8 and the other end portion is provided with a recess having an inner diameter larger than the inner diameter of the insertion hole.

Reference numeral 7 denotes a bottomed cylindrical body which is made of a non-magnetic material, accommodates the movable iron core 5 on the bottom side thereof, and makes the fixed iron core 6 face the movable iron core 5 toward the opening side. Store.

Reference numeral 8 denotes a first joining member, which is formed of a magnetic metal material such as iron into a rectangular shape and has an insertion hole at the center through which one end of the fixed iron core 6 is fixed before being fixed. The vicinity is airtightly joined to the cylindrical body 7.

Reference numeral 9 is a second joining member, which is made of a metallic material and is formed into a cylindrical shape having opening holes at both ends. In the second joining member 9, the opening hole on the one end side is airtightly joined to the opening end of the sealing container 2, and the other end is airtightly joined to the first joining member 8. , Fixed contacts 3a, 3
An airtight space for housing a and the movable contactor 4 is formed, and hydrogen or a gas mainly containing hydrogen is hermetically sealed in this airtight space.

A movable shaft 10 is formed into a substantially round bar shape, and one end of the movable shaft is inserted into an insertion hole provided in the central portion of the movable contactor 4. Reference numeral 11 denotes a contact pressure spring, which is formed in a coil shape and is held by a holding member 12 which will be described later to urge the movable contactor 4 in a direction of abutting the fixed contacts 3a, 3a. A holding member 12 holds the contact pressure spring 11 in a compressed suspension state so that the movable contact 4 is connected to the movable shaft 10, and is formed in a substantially U-shaped cross section.

A return spring 13 biases the movable iron core 5 in the direction in which the movable contact 4 is separated from the fixed contacts 3a, 3a, and is slightly larger than the inner diameter of the insertion hole of the fixed iron core 6. It is formed in a coil shape having a large inner diameter, is inserted into the movable shaft 10 inserted into the insertion hole of the fixed iron core 6, and one end thereof is fitted into the concave portion of the fixed iron core 6 and the position thereof is regulated.

Reference numeral 14 denotes a yoke, which forms a magnetic circuit together with the movable iron core 5, the fixed iron core 6, the first joining member 8 and the coil 15 described later. Reference numeral 15 denotes a coil, which is wound around a coil frame (not shown) and constitutes an electromagnet device together with the movable iron core 5, the fixed iron core 6 and the first joining member 8.

Reference numeral 16 denotes a housing which houses the sealed container 2 and the like, and is provided with an insertion hole through which the fixed terminal 3 is inserted.

Next, the operation of short-circuiting and opening between the fixed terminals 3 and 3 of the sealed contact device A having the above-mentioned configuration by an input operation signal will be described.

When an input operation signal is input to the sealed contact device A and the coil 15 is excited, the movable iron core 5 is attracted to the fixed iron core 6 and moves, so that the movable iron core 5 is fixed to the movable iron core 5. The shaft 10 moves. Then, the fixed contacts 3a, 3
The movable contactor 4 facing the a with a predetermined contact gap gradually reduces the contact gap, and eventually comes into contact with the fixed contacts 3a, 3a, and the fixed terminal is contacted via the movable contactor 4. Short circuit between 3 and 3.

When the input operation signal is stopped and the coil 15 is de-energized, the movable contactor 4 is mainly connected to the contact spring 1.
The movable contact 4 is separated from the fixed contacts 3a, 3a by returning with the urging force of 1 and the return spring 13, and the movable iron core 5 also moves a predetermined distance and returns to the original state. Then, the arc generated between the contacts at the time of returning is sufficiently extended in both end directions of the movable contactor 4 by the magnetic field of the magnetic means (not shown) and extinguished. As a result, the fixed terminals 3 and 3 are opened.

[0019]

The sealed contact device A described above.
When used as a relay for a power load, an electromagnetic switch, or the like, the movable contactor 4 is operated when an operation signal is erroneously input to the input side or excessive vibration is applied to the device for some reason. Is abutted against the fixed contacts 3a, 3a, and as a result, the fixed terminals 3, 3 are inadvertently short-circuited, which may cause one of secondary troubles.

In order to prevent this, the sealed contact device A is a machine for preventing the movable contact 4 from moving when it is mounted on equipment for which the fixed terminals 3 and 3 must not be short-circuited. It is preferable to provide a general safety mechanism. However, as described above, since the movable contactor 4 is housed in the airtight space, it is assumed that the mechanism for preventing the movable contactor 4 from mechanically moving becomes complicated, and the movable contactor 4 is realized at low cost. The difficulty was that it was a problem.

The present invention has been made in view of the above circumstances, and its object is to make contact points even when an operation signal is erroneously input to the input side or excessive vibration is applied to the device. An object of the present invention is to provide a sealed contact device having a safety mechanism that prevents short-circuiting between them with a simple configuration and at low cost.

[0022]

In order to achieve the above object, in a sealed contact device of the present invention, a sealed container made of an insulating material and a fixed contact are hermetically joined to the sealed container. A fixed terminal, and a movable contact that comes into contact with and separates from the fixed contact,
A movable iron core that is driven and moved in one direction, a fixed iron core that faces the movable iron core and sucks and drives the movable iron core in the one direction, and a bottomed tube that houses the movable iron core. A body, a first joining member that is airtightly joined to the cylindrical body, and hydrogen-tightly joined to the sealing container and the first joining member so that hydrogen or a gas mainly containing hydrogen is hermetically sealed. A second joint member that forms an airtight space for accommodating the contacts and the iron cores, a movable shaft connected to the movable iron cores, and a contact direction of the movable contacts to the contacts. And a holding member that holds the contact pressure spring in a compressed suspension state so that the movable contact is connected to the movable shaft, and a return that urges the movable iron core in one direction. Spring, yoke and coil for attracting and driving the movable iron core through the fixed iron core In the sealed contact device provided with a housing, it is characterized in that a forced locking means for preventing movement of said movable iron core.

Thus, the sealed contact device can be provided with a safety mechanism for preventing the movable iron core from moving.

In the sealed contact device of the present invention, it is preferable that the forcible locking means is a permanent magnet that magnetically blocks the movement of the movable iron core. As a result, the movable iron core is attracted to the permanent magnet and becomes hard to move.

Further, in the sealed contact device of the present invention,
The permanent magnet is fixed to a rotating member provided inside the housing so as to be rotatable in substantially the same plane as the bottom surface of the cylindrical body, and the rotating member is rotated from the outside of the housing. Is preferred. In this case, the movable iron core is attracted to the permanent magnet of the rotating member and becomes difficult to move.

Further, in the sealed contact device of the present invention, it is preferable that the permanent magnet is provided so as to be detachable from the outside of the housing. In this case, the movable iron core is attracted to the permanent magnet and becomes hard to move.

Further, in the sealed contact device of the present invention,
It is preferable that the permanent magnet is integrated with a holder arranged near the bottom surface of the cylindrical body. In this case, the permanent magnet of the holder is arranged at the bottom of the movable iron core, which makes it difficult for the movable iron core to move.

Further, in the sealed contact device of the present invention, it is preferable that an insertion hole communicating with the vicinity of the bottom surface of the cylindrical body is formed in the housing, and the holder is inserted into the insertion hole. This makes it difficult for the movable iron core to move due to the holder.

Further, in the sealed contact device of the present invention,
It is preferable that the forcible locking unit is a magnetic path cutting unit that attaches and detaches a part of the yoke of the magnetic circuit that moves the movable iron core by magnetic force. This makes it difficult for the movable iron core to be attracted to the fixed iron core when the coil is excited.

In the sealed contact device of the present invention, the magnetic path cutting portion is fixed to a rotating member provided so that a part of the yoke is rotatable inside the housing, It is preferable that the rotating member is formed so as to be rotatable from the outside of the housing. Then, by rotating the rotating member, the magnetic path of the magnetic circuit is disconnected.

Further, in the sealed contact device of the present invention,
It is preferable that the magnetic path cutting portion is formed such that a part of the yoke is removable from an insertion hole formed in the housing. In this case, the magnetic path of the magnetic circuit is cut by pulling out the holder.

[0032]

BEST MODE FOR CARRYING OUT THE INVENTION The sealed contact device of the present invention has a safety mechanism that prevents short-circuiting between contacts even when an operation signal is erroneously input to the input side or vibration is applied to the device. The purpose of being equipped was realized with a small number of parts and without making the entire device too large.

[0033]

1 to 11 are views showing an embodiment of a sealed contact device according to the present invention, and in the following description, parts such as the sealed container 2 to the housing 16 having the same structure as the conventional example will be described. Are denoted by the same reference numerals, and therefore, detailed description of the portions having the same reference numerals is omitted.

As shown in FIG. 1, the sealed contact device 1 according to this embodiment has a sealed container 2 made of an insulating material and a fixed contact 3.
Fixed terminals 3 and 3 having a and 3a and airtightly joined to the sealed container 2, and a movable contactor 4 that contacts and separates from the fixed contacts 3a and 3a.
The movable iron core 5 that is driven and moved in one direction, the fixed iron core 6 that faces the movable iron core 5 and is sucked and driven in one direction of the movable iron core 5, and the movable iron core 5 are stored. A bottomed tubular body 7 and a first joining member 8 that is airtightly joined to the tubular body 7.
And each of the contacts 3a, 3a and each of the iron cores 5, 6 are housed by hermetically bonding the sealing container 2 and the first bonding member 8 so that hydrogen or a gas mainly containing hydrogen is hermetically sealed. Second joining member 9 that forms an airtight space for moving, a movable shaft 10 that is connected to the movable iron core 5, and a contact pressure spring 11 that biases the movable contactor 4 in the contact direction of the contacts 3a, 3a. So that the movable contactor 4 is connected to the movable shaft 10 continuously.
Holding member 12 for holding the movable core 5 in a compressed suspension state, and the movable iron core 5
A return spring 13 for urging the movable iron core 5 in one direction, a yoke 14 and a coil 15 (neither shown) for attracting and driving the movable iron core 5 via the fixed iron core 6, and a housing 16.
In the sealed contact device 1 provided with, the forcible locking means for preventing the movable iron core 5 (not shown) from moving is provided.

In this case, the forcible locking means is the movable iron core 5
Is a permanent magnet 17 that magnetically blocks the movement. The permanent magnet 17 is inside the housing 16 and is the cylindrical body 7.
It is fixed to a rotary member 18 provided so as to be rotatable in a plane substantially the same as the bottom surface (not shown), and the rotary member 18 is rotated from the outside of the housing 16.

The rotating member 18 is for releasing the setting of the forcible lock by rotating it by a rotating member 20 which will be described later. For example, the rotating member 18 is formed of a metal material, a synthetic resin material or the like in a substantially L shape. A hole into which a turning member 20 to be described later is fitted is formed in one end portion 18a of the rotating member 18, and a permanent magnet 17 is attached to the other end portion 18c. Then, the rotary member 18 is internally provided in the housing 16 so as to be rotatable around a rotary shaft composed of the one end portion 18a and one base end portion 18b.

The rotating member 20 is fitted in a hole provided in one end portion 18a of the rotating member 18 to rotate the rotating member 18 around the above-described rotating shaft. For example, a metal material or a synthetic resin material is used. Etc. The rotating member 20 may be formed integrally with the rotating member 18.

In the sealed contact point device 1 having the above-described structure, as shown in the explanatory view of FIG.
When the permanent magnet 17 is rotated by (not shown) and is arranged at the bottom of the movable iron core 5 as shown in FIG. 2B, the magnetic force generated from the permanent magnet 17 causes the movable iron core 5 to move. It is possible to set a compulsory lock that makes 5 difficult to move. Then, since the movable shaft 10 fixed to the movable iron core 5 and the movable contactor 4 attached to the movable iron core 5 become difficult to move, it is difficult for the movable shaft 10 to come into contact with the fixed contacts 3a, 3a (neither shown). Become. As a result, the sealed contact device 1 operates with a safety mechanism that makes it difficult for the fixed terminals 3 and 3 to be short-circuited.

Further, in order to release the above-mentioned forced lock, the rotating member 18 is rotated by the rotating member 20 (not shown), and as shown in FIG.
However, it may be removed from the bottom of the movable iron core 5.

According to the sealed contact device 1 having this structure,
The setting of the forced lock means can be released from the upper surface of the device, and since the forced lock means does not project from the housing 16, it is suitable for high density mounting and use in a hybrid vehicle, electric vehicle, or the like. is there.

It should be noted that by appropriately marking the tip portion 18a of the rotating member 18, the setting release state of the forcible lock can be clearly shown on the upper surface of the sealed contact device 1.

Further, in the sealed contact device 1 of the present invention, as shown in FIG. 3, the permanent magnet 17 is integrated with the holder 19 arranged near the bottom surface of the cylindrical body 7 (not shown), It may be provided so as to be detachable from the outside of the housing 16 to form the compulsory locking means.

Also in the above configuration, as shown in the explanatory view of FIG. 4, when the holder 19 is attached to the bottom surface of the housing 16, the permanent magnet 17 is arranged at the bottom of the movable iron core 5, so that the permanent magnet is provided. A magnetic force generated from 17 sets a forced lock that makes it difficult for the movable iron core 5 to move. Also, to release the compulsory lock, the holder 19
Is removed from the bottom surface of the housing 16, and the permanent magnet 17
It suffices that the magnetic force of does not act on the movable iron core 5.

Further, in the sealed contact device 1 of the present invention, as shown in FIG. 5, the housing 16 is formed with an insertion hole 16a which communicates with the vicinity of the bottom surface of the cylindrical body 7, and the insertion hole 16a is permanently attached to this insertion hole 16a. Holder 1 formed by integrating magnets 17
The forced locking means may be formed so that 9 is inserted.

Also in the above structure, as shown in the explanatory view of FIG. 6, when the holder 19 is inserted, the permanent magnet 17 is arranged at the bottom of the movable iron core 5. In this case, since the distance between the movable iron core 5 and the permanent magnet 17 is shorter than that of the means for disposing the permanent magnet 17 outside the housing 16, the magnetic force generated from the permanent magnet 17 is stronger. It is possible to make it difficult to move more reliably. As a result, a more reliable forced lock can be set in the sealed contact device 1, and the safety is further enhanced.

Further, as shown in FIG. 7 (a), the holder 19 may be provided with a movement operation hole 19a at one end on the front side. In this case, as shown in FIG.
When the holder 19 is pulled out through the movement operation hole 19a by a predetermined length, the forced lock set on the sealed contact device 1 can be released. In this way, the forced lock setting can be easily released, and the forced lock setting can be released by the protruding state of the movement operation hole 19a from the housing 16.
The sealed contact device 1 can also be made explicit.

Further, in the sealed contact device 1 of the present invention, as shown in FIG.
Alternatively, a part of the yoke 14 (neither of which is shown) of the magnetic circuit that moves the magnetic field by the magnetic force can be used as a magnetic path cutting part for attaching and detaching. In the magnetic path cutting portion, a part of the yoke 14 (not shown) is fixed to a rotating member 18 provided so as to be rotatable inside the housing 16, and the rotating member 18 is rotatable from the outside of the housing 16. To be formed.

The yoke 14 is provided with the movable iron core 5, the fixed iron core 6, the first joining member 8 and the coil 15 together with the movable iron core 5.
A magnetic circuit for driving and moving (none of them is shown) is made of, for example, a magnetic material having a high magnetic permeability such as iron. The yoke 14 is formed so that a part 14a thereof can be attached and detached. When the part 14a is removed from the yoke 14, the magnetic path of the magnetic circuit described above can be cut.

The rotating member 18 is rotated by a rotating member 20 which will be described later to release the setting of the forced lock.
8a is provided with a hole into which a later-described turning member 20 is fitted,
A portion 14a of the yoke 14 was attached to the lower portion 18c, and was formed into a substantially L shape by using, for example, a metal material or a synthetic resin material. The rotary member 18 is attached to the upper portion 18a and the base portion 1
It is provided in the housing 16 so that it can rotate around a rotation axis composed of 8b.

The rotating member 20 is the upper portion 18 of the rotating member 18.
The rotary member 18 is rotated around the above-described rotary shaft by being fitted in the hole provided in a, and is made of, for example, a metal material or a synthetic resin material. The rotating member 20
May be formed integrally with the rotating member 18.

In the sealed contact device 1 having the above-described structure, as shown in the explanatory view of FIG. 9, the rotating member 18 is the rotating member 20.
When rotated by a yoke (not shown), a portion 14a of the yoke is converted into a yoke 14 (not shown) as shown in FIG.
Be removed from. Then, the magnetic path of the magnetic circuit including the movable iron core 5, the fixed iron core 6, the first joining member 8, the yoke 14 and the coil 15 (all not shown) is cut. As a result, even if the coil 15 is excited, the movable iron core 5 is fixed to the fixed iron core 6.
Therefore, the sealed contact device 1 can be forcibly locked.

According to the sealed contact device 1 having this structure,
Since the magnetic path cutting means for cutting the magnetic path of the magnetic circuit sets the forced lock, the permanent magnet 17 becomes unnecessary,
The number of parts is small.

Further, in the sealed contact device 1 of the present invention, as shown in FIG. 10, in the magnetic path cutting portion, a part 14a of the yoke 14 is formed in the housing 16 through hole 16a.
It can also be formed so as to be detachable from the inside.

Also in the above structure, as shown in the explanatory view of FIG. 11, when the part 14a of the yoke 14 is removed, the magnetic path of the magnetic circuit described above is cut, so that the sealed contact device 1 is provided. , You can set a mandatory lock.

By providing the sealed contact device 1 with the forcible locking means for both the permanent magnet and the magnetic path cutting portion,
It goes without saying that a more reliable safety mechanism that makes it difficult to short-circuit between terminals can be provided.

[0056]

The present invention is implemented as in the above-mentioned embodiment, and in the sealed contact device according to the first aspect, since the forcible locking means is provided, the operation signal is erroneously input to the input side. It is possible to provide a safety mechanism for preventing a short circuit between the contacts even when the contacts are exposed to vibration or excessive vibration is applied to the device.

Further, in the sealed contact device according to the second aspect, since the forcible locking means is a permanent magnet that magnetically blocks the movement of the movable iron core, the movable iron is generated by the magnetic force generated from the permanent magnet. A safety mechanism that makes it difficult to move the core can be provided.

Further, in the sealed contact device according to the third aspect, since the forced locking means does not project from the housing, this sealed contact device can be mounted on a substrate or the like with high density and used.

Further, in the sealed contact device according to the fourth aspect, since the permanent magnet is provided so as to be detachable from the outside of the housing, it becomes easy to release the setting of the forced locking means.

Further, in the sealed contact device according to the fifth aspect, since the permanent magnet is arranged in the vicinity of the bottom surface of the movable iron core, the magnetic force acting on the movable iron core becomes stronger, so that it is more reliable. You can set a mandatory lock.

Further, in the sealed contact device according to the sixth aspect of the invention, since the holder is inserted into the insertion hole provided in the housing, the released state of the forced lock is clearly defined by the protruding state of the holder. Can be made.

Further, in the sealed contact device according to the seventh aspect, since the forcible locking means is the magnetic path cutting portion of the magnetic circuit for moving the movable iron core, the permanent magnet is unnecessary, The number of parts is small.

Further, in the sealed contact device according to the eighth aspect, since the magnetic path cutting portion can be operated from the upper portion of the housing, the setting release of the forcible locking means becomes easy.

Further, in the sealed contact device according to the ninth aspect, since the holder integrated with a part of the yoke is pulled out, the forced lock setting is surely released.

[Brief description of drawings]

FIG. 1 is a perspective view showing a sealed contact device of the present invention.
(Example 1)

FIG. 2 is an explanatory view showing the sealed contact device. (Example 1)

FIG. 3 is an exploded perspective view showing the sealed contact device.
(Example 2)

FIG. 4 is an explanatory view showing the same sealed contact device. (Example 2)

FIG. 5 is an exploded perspective view showing the sealed contact device.
(Example 3)

FIG. 6 is an explanatory view showing the same sealed contact device. (Example 3)

FIG. 7 is an explanatory view showing the same sealed contact device. (Example 3)

FIG. 8 is a perspective view showing the sealed contact device. (Example 4)

FIG. 9 is an explanatory view showing the same sealed contact device. (Example 4)

FIG. 10 is an exploded perspective view showing the sealed contact device.
(Example 5)

FIG. 11 is an explanatory view showing the same sealed contact device. (Example 5)

FIG. 12 is an exploded perspective view showing a sealed contact device that is a conventional example of the present invention.

[Explanation of symbols]

1 Sealed contact device 2 sealed containers 3 fixed terminals 3a Fixed contact 4 Movable contact 5 movable iron core 6 fixed iron core 7 cylinder 8 First joining member 9 Second joining member 10 movable axes 11 Contact spring 12 Holding member 13 Return spring 14 Yoke 14a Part of Yoke 15 coils 16 housing 16a Insertion hole formed in housing 17 permanent magnet 18 Rotating member 19 holder

Claims (9)

[Claims] 1. A sealed container made of an insulating material, a fixed terminal which has a fixed contact and is hermetically bonded to the sealed container, a movable contactor which comes in contact with and separates from the fixed contact, and is driven in one direction. A movable iron core that moves, a fixed iron core that faces the movable iron core and sucks and drives the movable iron core in the one direction, a bottomed cylindrical body that houses the movable iron core, and the same cylindrical body. A first joining member that is airtightly joined to the sealing container and the first joining member so that hydrogen or a gas mainly containing hydrogen is hermetically sealed. A second joining member forming an airtight space for housing each iron core;
A movable shaft connected to the movable iron core, a contact pressure spring for urging the movable contact in the contact direction of each contact, and the contact pressure so that the movable contact is connected to the movable shaft. A holding member that holds a spring in a compressed suspension state, a return spring that urges the movable iron core in one direction, a yoke and a coil for attracting and driving the movable iron core through the fixed iron core. A sealed contact device comprising: a housing; and a forcible lock device for preventing movement of the movable iron core. 2. The sealed contact device according to claim 1, wherein the forced locking means is a permanent magnet that magnetically blocks the movement of the movable iron core. 3. The permanent magnet is fixed to a rotating member provided inside the housing so as to be rotatable in substantially the same plane as the bottom surface of the cylindrical body, and the rotating member is attached from the outside of the housing. The sealed contact device according to claim 2, which is rotated. 4. The sealed contact device according to claim 2, wherein the permanent magnet is provided so as to be detachable from the outside of the housing. 5. The sealed contact device according to claim 4, wherein the permanent magnet is integrated with a holder arranged near the bottom surface of the cylindrical body. 6. The sealed contact device according to claim 5, wherein an insertion hole communicating with the vicinity of the bottom surface of the cylindrical body is formed in the housing, and the holder is inserted into the insertion hole. 7. The sealed contact device according to claim 1, wherein the forcible locking means is a magnetic path cutting portion for attaching and detaching a part of the yoke of a magnetic circuit for moving the movable iron core by magnetic force. 8. The magnetic path cutting portion is fixed to a rotating member provided so that a part of the yoke is rotatable inside the housing, and the rotating member is rotatable from the outside of the housing. The sealed contact device according to claim 7, wherein the sealed contact device is formed as follows. 9. The sealed contact device according to claim 7, wherein the magnetic path cutting portion is formed such that a part of the yoke is removable from an insertion hole formed in the housing.