Magnetic contactor

Disclosed is a magnetic contactor. The magnetic contactor includes a frame, a holder, a movable core, a bobbin, a fixed core coupled to a side of the bobbin and configured to absorb the movable core with a magnetic force, an elastic member provided between the holder and the bobbin, a b-contact switch configured to sense a closing completion time of the movable contact by using a mechanical mechanism relationship with the movable core, an electronic circuit part configured to receive a sensing signal from the b-contact switch and limit a current applied to the coil, and a switch manipulation member provided at one end of the movable core and configured to operate the b-contact switch.

CROSS-REFERENCE TO RELATED APPLICATION

Pursuant to 35 U.S.C. §119(a), this application claims the benefit of earlier filing date and right of priority to Korean Application No. 10-2013-0124776, filed on Oct. 18, 2013, the contents of which are hereby incorporated by reference herein in its entirety.

BACKGROUND OF THE DISCLOSURE

1. Field of the Disclosure

The present disclosure relates to a magnetic contactor that prevents an overcurrent from flowing in a coil by using a b-contact switch.

2. Background of the Disclosure

Generally, a magnetic contactor is a device that switches power (a current) flowing in a main circuit by using the electromagnet principle.

In the magnetic contactor, a closing operation is normally performed in only a case where when the magnetic contactor is closed, namely, when a movable contact of main power is moved to and contacts a fixed contact, a transient current flows in a coil, and then, when a closed state is maintained, namely, when a contacted state of the contact is maintained, a normal current flows in the coil. Therefore, the coil is not damaged by the rising of a temperature when the insertion is maintained.

As described above, in order to solve a problem such as a coil being damaged, a b-contact switch included in a product limits a current applied to the coil so that an overcurrent does not flow in the coil in a closing operation of the magnetic contactor.

FIG. 1Ais a circuit diagram of an electronic circuit part applied to a magnetic contactor. In the electronic circuit part of the magnetic contactor, a plurality of electronic elements for controlling a current flowing a coil L are mounted on a printed circuit board (PCB).

The electronic circuit part includes a plurality of external power input terminals P1and P2which receive external power, a bridge diode B/D which is disposed between the external power input terminals P1and P2and the coil L, a b-contact switch SW which is disposed between the external power input terminals P1and P2and the bridge diode B/D, and a capacitor C that is connected to both ends of the b-contact switch SW.

In this case, the coil L is provided in a state of being wound around a bobbin that is an internal element of a product. When external power is alternating current (AC) power, the bridge diode B/D converts the AC power into direct current (DC) power.

To describe a flow path of the external power, the magnetic contactor is closed, and when the external power (an external current) is applied through the external power input terminals P1and P2, the applied external current flows to the coil L through the b-contact switch SW having low impedance to drive the coil L. The b-contact switch SW is switched off simultaneously with the driving of the coil L, and thus, the applied external current flows to the coil L through the capacitor C having high impedance. Therefore, an overcurrent which is applied to the coil L when a closed state of the magnetic contactor is maintained is limited.

FIG. 1Bis an exploded assembly view of a b-contact switch and a holder in a lower frame of a prior art magnetic contactor. InFIG. 1B, a holder20is movably equipped in an upper frame, and a bobbin is provided in a lower frame12.

When external power is applied to a coil which is wound around the bobbin, a fixed core is changed to an electromagnet by a magnetic field which is generated around the coil, and thus, a movable core is absorbed into a fixed core by a magnetic force. At this time, the holder20coupled to an upper portion of the movable core is lowered, and presses a b-contact switch SW to switch off the b-contact switch SW.

However, in the prior art magnetic contactor, when a size of a product is large, the b-contact switch SW may be disposed at each of left and right sides (sides in a width direction) of the product. However, when a product is miniaturized, a free space in which the b-contact switch SW is provided is sufficient, and for this reason, it is difficult to miniaturize the product. Also, when the b-contact switch SW cannot be disposed at each of left and right sides of a product, it is difficult to implement a normal operation.

SUMMARY OF THE DISCLOSURE

Therefore, an aspect of the detailed description is to provide a magnetic contactor in which when a product is miniaturized, a space which a b-contact switch is provided is secured, and a normal operation of the b-contact switch is realized.

To achieve these and other advantages and in accordance with the purpose of this specification, as embodied and broadly described herein, a magnetic contactor includes a frame, a holder, a movable core, a bobbin, a fixed core, an elastic member, a b-contact switch, an electronic circuit part, and a switch manipulation member.

The frame may include a fixed contact which is fixed to and provided in the frame.

The holder may include a movable contact.

The movable contact may be movably provided in the frame.

The movable contact may contact the fixed contact.

The movable core may be coupled to the holder to interoperate with the holder.

The bobbin may be fixed to and provided in the frame, and configured to include a coil.

The fixed core may be coupled to a side of the bobbin, magnetized, and configured to absorb the movable core with a magnetic force.

The elastic member may be provided between the holder and the bobbin, and may restore a position of the movable core.

The b-contact switch may be configured to sense a closing completion time of the movable contact by using a mechanical mechanism relationship with the movable core.

The electronic circuit part may be configured to receive a sensing signal from the b-contact switch and limit a current applied to the coil.

The switch manipulation member may be provided at one end of the movable core, and configured to operate the b-contact switch.

In the above-described embodiment of the present invention, a disposed position of the b-contact switch is changed to a lower portion of a product in comparison with the existing product, and thus, a size of the product can be reduced.

Moreover, without operating the b-contact switch by using the existing holder, the movable core is included in the switch manipulation member, and thus, despite the b-contact switch being provided at a lower portion of a product, an operation of the b-contact switch is realized by the switch manipulation member. Accordingly, a product can be miniaturized.

The frame may include a first frame and a second frame.

The first frame may accommodate the holder.

The second frame may be adjacently assembled with the first frame.

The second frame may internally accommodate the bobbin and the fixed core.

The b-contact switch may be provided in the second frame.

The b-contact switch may be contactably disposed within a moving distance range of the switch manipulation member.

The electronic circuit part may be provided at a width-direction side of the bobbin in parallel with a moving direction of the movable core.

The b-contact switch may be disposed at an end of one side of the electronic circuit part and on a moving line of the switch manipulation member.

The switch manipulation member may include a switch manipulation body, a switch manipulation part, and a switch manipulation projection.

The switch manipulation part may be provided to protrude at an end of one side of the switch manipulation body.

The switch manipulation part may be disposed to be separated from the b-contact switch with an interval in a moving direction of the movable core.

The switch manipulation projection may be formed at the switch manipulation part to protrude toward the b-contact switch.

The switch manipulation projection may be formed in an embossed shaped at an end of the switch manipulation part.

According to a first embodiment of the present invention, the holder may include a guide groove formed at one end of the holder.

The movable core may include a support and a supporting pin.

The support may be provided at the switch manipulation part.

The support may include an inserting hole at each of both sides of the support.

The supporting pin may be inserted into the insertion hole to pass through the insertion hole.

Both ends of the supporting pin may be inserted into and coupled to the coupling part of the holder to connect the holder to the support.

According to a second embodiment of the present invention, the holder may include a guide groove formed at one end of the holder.

The movable core may include a support provided at the switch manipulation part.

The support may include a sliding projection which is formed at each of both ends of the support, and may be inserted into and coupled to the guide groove of the holder.

The b-contact switch may include a switch body and a switch operation member.

The switch body may include a movable contact and a fixed contact.

The switch operation member may be provided at one end of the switch body.

The switch operation member may be pressurized by the switch manipulation member.

The switch operation member may switch off the movable contact and fixed contact of the b-contact switch.

The switch operation member may have a strip type in which a length is longer than a width, may be provided at one end of the switch body to be inclined in a hinge structure, and may have elasticity.

A contact terminal having an arc shape may be provided at an end of the switch operation member.

As described above, in the magnetic contactor according to an embodiment of the present invention, the b-contact switch is disposed at a lower portion of a product, and thus, the product is miniaturized. Also, even without enlarging a size of the product, an operation of the b-contact switch is realized by using the switch manipulation member which is provided in the movable core.

DETAILED DESCRIPTION OF THE DISCLOSURE

The present invention relates to a magnetic contactor in which as a product is miniaturized, a space which a b-contact switch is provided is secured in the product, and an operation of the b-contact switch is realized.

FIG. 2is a perspective view of a magnetic contactor according to an embodiment of the present invention.

The magnetic contactor according to an embodiment of the present invention includes a frame110, a holder120, a movable core130, an elastic member140, a bobbin150, a b-contact switch172, and an electronic circuit part170.

The frame110, for example, includes a first frame111and a second frame112which are respectively disposed at an upper portion and a lower portion in a moving direction of the movable core130. The first and second frames111and112are detachably assembled. An accommodating space is provided in the frame110, and accommodates the holder120, the movable core130, the elastic member140, the bobbin150, the b-contact switch172, and the electronic circuit part170.

A plurality of fixed contacts113are respectively provided in parallel at a power source side and a load side and in the first frame111. In this case, when a main power is three-phase AC power, the fixed contacts113may be disposed at the power source side and the load side to be separated from each other in a width direction of the frame110for each of R, S, and T phases.

The holder120includes a plurality of movable contacts123that are movably provided in a vertical direction in the first frame111, and is formed in parallel to protrude toward the power source side and the load side. Also, a long side of the holder120is disposed in parallel with the width direction of the frame110.

The movable contacts123are elastically supported by an elastic spring, and are respectively disposed on the fixed contacts113to be separated from each other.

The movable core130is formed in a cylindrical structure, and is insertable into the bobbin150. Therefore, an internal space occupied by the movable core130can be minimized in comparison with a prior art E-shaped movable core130.

Moreover, the movable core130may include a switch manipulation member which is provided at an upper portion, and manipulate the b-contact switch172.

The switch manipulation member may include a switch manipulation body132, which has a plate structure, and a switch manipulation part133which is provided to protrude in one side direction from the switch manipulation body132. The switch manipulation member may mechanically contact the b-contact switch172.

The movable core130is coupled to and supported by a bottom of the holder120by using a support134. The movable core130lowers the movable contact123to the fixed contact112to contact the movable contact123with the fixed contact112by using the holder120.

The bobbin150includes a cylindrical bobbin body151, which is long disposed in a vertical direction, and a plurality of core insertion parts152which are respectively disposed at an upper end and lower end of the bobbin body151in a radius direction.

The bobbin body151has a hollow part154which is formed therein. The movable core130may be vertically inserted into the bobbin body151through the hollow part154. Also, a coil156is wound around the bobbin body151, and thus, when external power is applied to the coil156, a magnetic field is generated.

The core insertion part152includes an opening which enables the fixed core to be inserted.

A plurality of external power input terminals may be provided at left and right ends of the core insertion part152of the bobbin150, and external power may be applied to the coil156through external power input terminals.

The elastic member140may be a compression coil spring which is formed in order for a diameter to be reduced progressively closer to an upper direction. An upper end of the compression coil spring elastic-supports the bottom of the holder120, and a lower end of the compression coil spring is fixed to and supported by an upper end of the bobbin150.

The fixed core160forms a box structure to surround an outer surface of the coil156in an axial direction of the cylindrical bobbin body151. In this case, the fixed core160may be separated into first and second fixed cores161and162in a width direction of the bobbin150.

The first and second fixed cores161and162are detachably assembled with the core insertion part152at both sides of the bobbin150in the width direction, and thus are easy to assemble and maintain. In comparison with a prior art E-shaped fixed core160, an internal space of a product occupied by the fixed core160is minimized, and thus, a free space in which the b-contact switch172is provided can be secured at a lower portion (the second frame112) of the product.

The electronic circuit part170includes a PCB171which is equipped with various electronic elements, and controls an external source current flowing in the coil156.

The b-contact switch172is included in the PCB171. When the movable contact123is closed, a closing completion time is sensed by a mechanical mechanism with the movable core130. When the closing completion time is sensed, an internal contact of the b-contact switch172is inverted from switch-on to switch-off, whereby a flow direction of a current is changed.

In this case, the b-contact switch172may be disposed within a moving distance range of the movable core130so as to maintain a mechanical mechanism relationship with the movable core130, and may operate according to a movement of the movable core130.

A closing operation of the movable contact123denotes that the movable contact123moves toward the fixed contact113, and the closing completion time denotes that the movable contact123contacts the fixed contact113.

Moreover, the capacitor173is included in the PCB171. An external source voltage is dropped simultaneously with an inversion of the b-contact switch172, and thus, a current applied to the coil156is reduced. Therefore, when a closed state of the movable contact123is maintained, an overcurrent of the coil156is limited.

The closed state of the movable contact being maintained denotes a state in which the movable contact123contacts the fixed contact113.

Here, the PCB171may be coupled to width-direction one side of the bobbin150to be adjacent to the fixed core160, and may be equipped in a lower portion of a product, namely, the inside of the second frame112by using a free space.

In the prior art, the b-contact switch172is disposed at each of left and right sides of a product, and thus, a size of the product is enlarged. However, in an embodiment of the present invention, the b-contact switch172is disposed at a lower portion of a product, more particularly, at an upper portion of the PCB which is coupled to the width-direction one side of the bobbin150built into the second frame112. Accordingly, despite a product being miniaturized, a space in which the b-contact switch172is provided can be secured.

In the prior art, since the b-contact switch172is disposed at a side of a product, the holder120may directly press and operate the b-contact switch172. However, in an embodiment of the present invention, since the b-contact switch172is disposed at a lower portion of a product, namely, in the second frame112, it is impossible for the holder120to operate the b-contact switch172.

FIG. 3is a perspective view of a movable core130according to a first embodiment of the present invention.FIG. 4is a perspective view illustrating a state before the movable core130ofFIG. 3is coupled to a holder120.FIG. 5is a perspective view illustrating a state after the movable core130ofFIG. 3is coupled to the holder120.FIG. 6is a cross-sectional view illustrating a state in which the movable core130is coupled to the holder120.

In an embodiment of the present invention, the movable core130may directly operate the b-contact switch172by using a mechanical mechanism relationship between the movable core130and the b-contact switch172.

The movable core130may include a switch manipulation part133which is provided at an upper portion of the movable core130, and thus, when the movable core130is lowered toward the fixed core160, the b-contact switch172may operate according to a contact of the switch manipulation part133.

Here, the b-contact switch172may be disposed within a moving distance range of the switch manipulation part133, and may contact the switch manipulation part133.

The movable core130may include a cylinder-shaped movable body131that is long provided in a vertical direction, a plate-shaped switch manipulation body132that is provided at an upper end of the movable body131, and the switch manipulation part133which is provided at one side of the switch manipulation body132to protrude.

The switch manipulation body132may be manufactured separately from the movable body131. A connecting shaft131ahaving a small diameter is provided at an upper end of the movable body131to protrude, for fixing the switch manipulation body132to the movable body131.

A connecting hole is formed in the switch manipulation body132to pass through the switch manipulation body132, and the connecting shaft131agoes to an upper portion of the switch manipulation body132through the connecting hole.

Moreover, a support134may be disposed between the switch manipulation body132and the bottom of the holder120, and may be coupled to the switch manipulation body132as one body through the connecting hole131a. A connecting hole is formed in the support134to pass through the support134, and the connecting shaft131ais coupled to the support134through the connecting hole. An upper end of the connecting shaft131amay be riveted, and thus, the support134and the switch manipulation body132may be stacked on and coupled to an upper end of the movable body131as one body.

Moreover, an anti-torsion member which is provided at a top of the switch manipulation body132may prevent the switch manipulation part133of the switch manipulation body132from being rotated in the movable core130.

The support134may include a supporting plate, which is stacked on the top of the switch manipulation body132, and a side plate which is bent toward the holder120and at both ends of the supporting plate. In this case, a long hole may be included in the side plate.

A supporting pin135may be inserted into the long hole of the support134, and the support134may be connected to the holder120through the supporting pin135.

The supporting pin135may have a strip-type plate structure that has a length longer than a width and is thin in thickness, and both ends of the supporting pin135may be bent to be rounded.

Moreover, a guide projection125is formed at the bottom of the holder120, and a guide groove125ais formed at an inner surface of the guide projection125.

In this case, the both ends of the supporting pin135are inserted into the guide groove125aof the holder120, and thus, the supporting pin135is coupled to the holder120in a slide type in a width direction (a direction from the bottom of the holder120to a short side) of the holder120. Therefore, the support134is coupled to the holder120.

Accordingly, the movable core130and the holder120may operate as one body. Also, the movable core130may be mechanically connected to a movable contact123included in the holder120, and may move the movable contact123to a fixed contact113.

FIG. 7is a perspective view illustrating a state in which a movable core230according to a second embodiment of the present invention is coupled to a holder120, andFIG. 8is a perspective view illustrating a state in which a movable core330according to a third embodiment of the present invention is coupled to a holder120.

A support234of the movable core230according to the second embodiment may not include the supporting pin135unlike the first embodiment, and may have a structure in which a sliding projection234ais bent outward from a supporting plate, and a bent portion is inserted into a guide groove125aof the holder120in a slide type, whereby the support234is coupled to the holder120.

A support334of the movable core330according to the third embodiment may not include the supporting pin135unlike the first embodiment, and may have a structure in which a sliding projection334ais bent inward from a supporting plate, and a bent portion is inserted into a guide groove325aof the holder120in a slide type, whereby the support334is coupled to the holder120.

FIG. 9is a perspective view of a movable core according to a second embodiment of the present invention.

A switch manipulation projection233ahaving an embossed shape may be formed at a switch manipulation part133of a movable core130illustrated inFIG. 9, and may protrude toward a contact terminal172a′ of a b-contact switch172, thereby closely maintaining a mechanical mechanism relationship between the movable core130and the b-contact switch172.

FIG. 10is a side view of a b-contact switch172according to an embodiment of the present invention.

The b-contact switch172illustrated inFIG. 10may include a switch body172bhaving a tetragonal box structure and a switch operation lever172awhich is mounted on an upper end of the switch body172b.

The switch body172bmay include a movable contact123and a fixed contact113which are provided in the switch body172b, and the movable contact123may be separated from or may contact the fixed contact113according to an operation of the switch operation lever172a. In this case, the movable contact123may be adhered to one side of the switch body172bso as to surface-contact an upper end of the PCB171of the electronic circuit part170.

The switch operation lever172amay have a rectangular plate structure which is long in length and is thin in thickness. One end of the switch operation lever172ais coupled in a hinge structure, and the other end of the switch operation lever172amay be pressed by a switch manipulation projection133a, and when the press is released, the switch operation lever172amay be restored to the original position by an elastic restoring force of the switch operation lever172aitself.

In this case, a contact terminal17a′ having an arc shape may be provided at the other end of the switch operation lever172a, and thus, a contact with the switch manipulation projection133ais smoothly maintained.

Moreover, a contact of the b-contact switch172normally is in a switch-on state, and when the switch operation lever172ais pressed, the contact of the b-contact switch172is inverted into a switch-off state.

FIG. 11is a cross-sectional view of a magnetic contactor according to an embodiment of the present invention.

An operating state of the magnetic contactor will now be described in detail with reference toFIG. 11.

When an external source current is applied to a coil156, a magnetic field is generated around the coil156, and a bobbin150and a fixed core160are magnetized by the magnetic field. A magnetic force is generated in the magnetized bobbin150and fixed core160, and a movable core130is absorbed into the fixed core160by the magnetic force.

Subsequently, due to the external source current, a movable contact123of an electronic circuit part170is moved to and contacts the fixed contact113, and thus, a circuit is connected, whereby main power flows in a load.

At this time, a switch manipulation projection133aof a switch manipulation body132coupled to an upper end of the movable core130presses a contact terminal172a′ of a switch operation lever172aof a b-contact switch172, and thus, the b-contact switch172is switched off. Simultaneously, the external source current is dropped by passing through a capacitor173of the electronic circuit part170, and the dropped external source current flows to the coil156, thereby maintaining a contact between the movable contact123and the fixed contact113.

When the external source current dissipates, the magnetic field of the coil156dissipates, and an absorbing force of the fixed core160is released. Therefore, the movable core130is pushed up to the original position by an elastic restoring force of an elastic member140which is disposed between the holder120and the bobbin150, and thus, the movable contact123is separated from the fixed contact113, whereby the main power is cut off.

Therefore, according to an embodiment of the present invention, a disposed position of the b-contact switch172is changed to a lower portion of a product in comparison with the existing product, and thus, the product can be miniaturized. Also, a position of the b-contact switch172is changed, and thus, the switch manipulation part133is provided at a movable part, thereby realizing an operation of the b-contact switch172.

As described above, in the magnetic contactor according to an embodiment of the present invention, the b-contact switch is disposed at a lower portion of a product, and thus, the product is miniaturized. Also, even without enlarging a size of the product, an operation of the b-contact switch is realized by using the switch manipulation member which is provided in the movable core.