Patent Description:
In general, an electromagnetic contactor is a kind of electrical circuit switchgear that transmits a mechanical driving signal and a current signal using the principle of an electromagnet, and is installed in various industrial facilities, machines, and vehicles. An electromagnetic contactor is for instance known from <CIT>.

A magnetic contactor includes a fixed contact tip and a moving contact tip that open and close an electric circuit for supplying electricity to a load such as a motor, a coil and a core (fixed core and movable core) that constitute an electromagnet for performing an opening operation of the moving contact tip, and a crossbar that is a connecting mechanism for transferring movement of the electromagnet to the contact tip.

When a specified voltage is applied to the coil, an excitation current flows, to generate magnetic flux in the fixed core, which then turns into a magnet. Accordingly, the movable core is attracted toward the fixed core. A moving contact and the moving contact tip are coupled to the crossbar which is connected to the movable core, so as to be movable in response to the movement of the movable core, and are brought into contact with a fixed contact and the fixed contact tip which are fixed to the frame, so as to close the circuit (closed state, electricallyconnected state).

When the voltage applied to the coil is cut off, excitation (magnetization) of the fixed core is released and the movable core returns to its original position by a return spring, causing the moving contact tip to be separated from the fixed contact tip, thereby breaking the circuit (open state).

When the circuit is opened/closed, an arc is generated between the contact tips, and is extinguished by an arc box and a grid disposed in the arc box.

<FIG> is a cutoff perspective view illustrating an electromagnetic contactor according to the related art.

In general, the configuration of the electromagnetic contactor includes a case (arc box) <NUM>, a frame <NUM>, a fixed contact tip <NUM>, and a moving contact tip <NUM>, and also typically includes an electric actuator for driving the moving contact tip <NUM> such that opening and closing between contact tips can be controlled by an electric signal.

The fixed contact tip <NUM> is connected to a power supply source or a load, and the moving contact tip serves as a switch that is brought into contact with or separated from the fixed contact tip <NUM>.

The frame <NUM> is divided into a lower frame 1a and an upper frame 1b to accommodate the fixed contact tip <NUM>, a moving contact tip <NUM>, and the electric actuator therein.

The electric actuator is a kind of electromagnet that forms an electromagnetic field, in response to power-on of a power supply source, so as to generate an electric attraction, and includes a fixed core <NUM>, a movable core <NUM>, a coil <NUM>, a bobbin <NUM>, and a crossbar <NUM>.

Here, a coil assembly in which the coil <NUM> and the bobbin <NUM> fixing the coil <NUM> are coupled is inserted into the lower frame 1a. When external power is applied to the coil <NUM>, a current flows in the coil <NUM>, and the fixed core <NUM> is excited to attract the movable core <NUM>. As the movable core <NUM> moves downward, the crossbar <NUM> and the moving contact tip <NUM> move together, and the moving contact tip <NUM> comes into contact with the fixed contact tip <NUM>, such that the circuit is electrically connected.

<FIG> is a view illustrating an electromagnetic contactor according to another implementation of the related art, and <FIG> is a lateral cross-sectional view of the electromagnetic contactor.

The frame that protects and fixes all parts of the electromagnetic contactor roughly includes a lower frame 1a, an upper frame 1b, and an arc box 1c.

Conventionally, in order to fix the three parts, the lower frame 1a and the upper frame 1b are fastened with nuts <NUM> and screws <NUM>, and the arc box 1c is fixed to the upper frame 1b with a fastening member <NUM> such as a rivet assembly, etc..

However, the fastening member <NUM> used when assembling the arc box 1c has weak fixing force, and thereby damaged or disassembled due to a fault current when a short-circuit accident occurs.

The present disclosure has been devised to solve the above-described problems, and one aspect of the present disclosure is to provide an electromagnetic contactor capable of preventing an arc box from being separated from a frame.

An electromagnetic contactor in accordance with one implementation of the present disclosure includes a lower frame, an upper frame coupled to an upper portion of the lower frame, and an arc cover coupled to an upper portion of the upper frame. A first coupling part protrudes from one surface of the lower frame such that a fastening member is coupled, a second coupling part protrudes from one surface of the upper frame and is connected to the first coupling part, such that the fastening member is fastened, and a third coupling part protrudes from one surface of the arc cover and is connected to the second coupling part, such that the fastening member is fastened. The fastening member is coupled through the first coupling part, the second coupling part, and the third coupling part.

Here, the first coupling part has a predetermined length from an upper end portion of the lower frame, and is shorter than a length (height) of the lower frame.

The second coupling part has a length from an upper end portion to a lower end portion of the upper frame.

The third coupling part has a predetermined length from a lower end portion of the arc cover, and may be shorter than a length (height) of the arc cover.

A first fastening hole may be formed vertically through the first coupling part such that the fastening member is coupled, a second fastening hole may be formed vertically through the second coupling part such that the fastening member is coupled, and a third fastening hole may be formed vertically through the third coupling part such that the fastening member is coupled.

A first auxiliary fastening hole is formed through the first coupling part to be adjacent to the first fastening hole, a second auxiliary fastening hole is formed through the second coupling part to be adjacent to the second fastening hole, and an auxiliary fastening member is provided to be coupled through the first auxiliary fastening hole and the second auxiliary fastening hole.

The first coupling part, the second coupling part, and the third coupling part may be formed respectively at the lower frame, the upper frame, and the arc cover, on each of both side portions of one surface thereof.

The first coupling part, the second coupling part, and the third coupling part may be formed respectively at the lower frame, one surface of the upper frame, and one surface of the arc cover, on each of both opposite surfaces thereof.

The first coupling part, the second coupling part, and the third coupling part may be formed on a surface where a fixed contact arm is not exposed based on the upper frame.

A top cover may be coupled to an upper portion of the arc cover. The top cover may have a cover fastening hole, the arc cover may have an inter-phase insulating groove, and a cover fastening member may be provided to be coupled through the cover fastening hole and the inter-phase insulating groove.

According to an electromagnetic contactor according to an implementation of the present disclosure, a first coupling part, a second coupling part, and a third coupling part protrudes from an upper frame, a lower frame, and an arc cover, respectively, and a coupling member is provided to be coupled through the first coupling part, the second coupling part, and the third coupling part, which can secure stable coupling force of the arc cover.

The coupling of the upper frame, the lower frame, and the arc cover is achieved at a time by the coupling member, thereby enhancing efficiency of an assembling operation.

Auxiliary fastening members for fixing the upper frame and the lower frame can be additionally provided to increase coupling force between the upper frame and the lower frame.

A cover coupling member may be provided for a top cover disposed on an upper portion of the arc cover, thereby enhancing the coupling force.

This can prevent separation of the arc cover even if an impact is caused due to a repeated arc extinguishing operation.

Hereinafter, preferred implementations of the present disclosure will be described with reference to the accompanying drawings, so that a person skilled in the art can easily carry out the invention. It should be understood that the technical idea and scope of the present disclosure are not limited to those preferred implementations.

<FIG> and <FIG> are a perspective view, an exploded perspective view, and a lateral view in a direction A illustrating an enclosure of an electromagnetic contactor in accordance with one implementation of the present disclosure. <FIG> is a partial lateral view in a direction B in <FIG>, and is a partial cross-sectional view taken along the line C-C.

Hereinafter, an electromagnetic contactor in accordance with each implementation of the present disclosure will be described in detail with reference to the accompanying drawings.

An electromagnetic contactor according to an implementation of the present disclosure includes a lower frame <NUM>, an upper frame <NUM> coupled to an upper portion of the lower frame <NUM>, and an arc cover <NUM> coupled to an upper portion of the upper frame <NUM>. A first coupling part <NUM> protrudes from one surface of the lower frame <NUM> such that a fastening member <NUM> is fastened thereto, a second coupling part <NUM> protrudes from one surface of the upper frame <NUM> and is connected to the first coupling part <NUM> such that the fastening member <NUM> is fastened thereto, a third coupling part <NUM> protrudes from one surface of the arc cover <NUM> and is connected to the second coupling part <NUM> such that the fastening member <NUM> is fastened thereto. The fastening member <NUM> is fastened so as to connect the first coupling part <NUM>, the second coupling part <NUM>, and the third coupling part <NUM>.

Frames <NUM>, <NUM>, and <NUM> may also be referred to as an enclosure, and may be provided to accommodate and support components of the electromagnetic contactor. The frames <NUM>, <NUM>, and <NUM> include the lower frame <NUM>, the upper frame <NUM>, and the arc cover <NUM>.

The lower frame is provided. The lower frame <NUM> may be made of an insulating material such as a synthetic resin material. The lower frame <NUM> may have an open upper surface and define an accommodation space therein.

A flange <NUM> may protrude from a bottom surface of the lower frame <NUM>. The bottom surface of the lower frame <NUM> may be supported by the ground or an attached portion so as to stably maintain embedded components.

An accessory device such as an auxiliary contact device <NUM> may be disposed on one side surface of the lower frame <NUM>.

A coil assembly <NUM> may be accommodated inside the lower frame <NUM>. The coil assembly <NUM> may be installed on a coil assembly mounting cassette <NUM>.

A fixed core <NUM> having a shape like "E" may be disposed in a central portion and a peripheral portion of the coil assembly <NUM>.

The first coupling part <NUM> protrudes from one side surface of the lower frame <NUM>. The first coupling part <NUM> extends downward from an upper end portion of the lower frame <NUM> by a predetermined length (thickness). In other words, the first coupling part <NUM> does not extend to a lower end portion of the lower frame <NUM>. That is, the length (thickness) of the first coupling part <NUM> is shorter than a length (height) of the lower frame <NUM>.

A first fastening hole <NUM> may be formed through the first coupling part <NUM> in a vertical direction (in an up and down direction). The fastening member <NUM> may be coupled to the first fastening hole <NUM>.

In addition, a first auxiliary fastening hole <NUM> is formed through the first coupling part <NUM> in the vertical direction. The first auxiliary fastening hole <NUM> may be formed adjacent to the first fastening hole <NUM>.

The first coupling part <NUM> and the first fastening hole <NUM> may be formed at each of both side portions (both end portions) on one surface of the lower frame <NUM>. That is, the first coupling parts <NUM> and the first fastening holes <NUM> may be formed as a pair on the one surface. At this time, the first coupling parts <NUM> and the first fastening holes <NUM> formed on the both side portions of the one surface may be symmetrical with each other.

The first coupling part <NUM> and the first fastening hole <NUM> may be formed at each of the both side portions (both end portions) of the lower frame <NUM> that are symmetrical with each other. At this time, the first coupling parts <NUM> and the first fastening holes <NUM> formed on the both side portions may be formed symmetrically with each other. That is, the first coupling parts <NUM> and the first fastening holes <NUM> may be formed as pairs on both opposite side surfaces of the lower frame <NUM>, respectively.

A protrusion <NUM> may protrude upward from one side surface of the lower frame <NUM>. The protrusion <NUM> may be formed on the surface on which the first coupling part <NUM> protrudes. The protrusion <NUM> may be formed on each of both opposite side surfaces of the lower frame <NUM>.

The upper frame <NUM> is disposed. The upper frame <NUM> may be made of an insulating material such as a synthetic resin material. The upper frame <NUM> may have an open lower surface and define an accommodation space therein.

The crossbar <NUM> may be installed through the upper frame <NUM> to be movable up and down. In the case of a plurality of phases, the crossbar may be provided to protrude for each phase. In the case of three phases, the crossbar <NUM> may be formed in a shape of a trident to protrude for through of the three phases.

A movable core (not illustrated) may be coupled to a lower portion of the crossbar <NUM>. The movable core may be moved downward by being attracted to the fixed core <NUM>, which is magnetized when external power is applied to the coil assembly <NUM> and a magnetic flux is produced accordingly. Here, since the crossbar <NUM> is coupled to the movable core, the crossbar <NUM> may also be moved downward together.

A fixed contact arm <NUM> may be disposed on an upper surface of the upper frame <NUM>. The fixed contact arm <NUM> may be disposed for each phase. The fixed contact arms <NUM> may be classified for each phase into a fixed contact arm disposed at a power source side and a fixed contact arm disposed at a load side. A terminal may be formed on an end portion of the fixed contact arm <NUM>. That is, the fixed contact arm <NUM> may be integrally formed with the terminal.

An inter-phase insulating wall <NUM> may be disposed between adjacent fixed contact arms <NUM>. The inter-phase insulating wall <NUM> can prevent arcs generated at the terminal from expanding into adjacent phases.

The second coupling part <NUM> protrudes from one side surface of the upper frame <NUM>. Here, the surface on which the second coupling part <NUM> is formed may be a surface on which the fixed contact arm <NUM> is not exposed. The second coupling part <NUM> has a length (thickness, height) from an upper end portion to a lower end portion of the upper frame <NUM>. In other words, the second coupling part <NUM> is formed from the upper end portion to the lower end portion of the upper frame <NUM>, not only on a portion of the upper frame <NUM>, in the vertical (lengthwise) direction. That is, the second coupling part <NUM> has the same length (thickness) as the length (height) of the upper frame <NUM>.

A second fastening hole <NUM> may be formed through the second coupling part <NUM> in a vertical direction (in an up and down direction). The fastening member <NUM> may be coupled to the second fastening hole <NUM>.

A second auxiliary fastening hole <NUM> is formed through the second coupling part <NUM> in the vertical direction. The second auxiliary fastening hole <NUM> may be formed adjacent to the second fastening hole <NUM>.

The second coupling part <NUM> and the first fastening hole <NUM> may be formed at each of both side portions (both end portions) on one surface of the upper frame <NUM>. That is, the first coupling parts <NUM> and the first fastening holes <NUM> may be formed as a pair on the one surface. At this time, the second coupling parts <NUM> and the second fastening holes <NUM> formed on the both side portions of the one surface may be symmetrical with each other.

The second coupling part <NUM> and the second fastening hole <NUM> may be formed on both side surfaces of the upper frame <NUM> that are symmetrical with each other. At this time, the second coupling parts <NUM> and the second fastening holes <NUM> formed on the both side portions may be symmetrical with each other. That is, the second coupling parts <NUM> and the second fastening holes <NUM> may be formed as pairs on both opposite side surfaces of the upper frame <NUM>, respectively.

The second coupling part <NUM> and the second fastening hole <NUM> may be formed to communicate with the first coupling part <NUM> and the first fastening hole <NUM>. That is, they may be formed on a surface in the same direction. This surface may be a surface on which the fixed contact arm <NUM> is not exposed at the upper frame <NUM>.

A concave portion <NUM> corresponding to the protrusion <NUM> of the lower frame <NUM> may be formed on one side surface of the upper frame <NUM>. The concave portion <NUM> may be formed on each of both opposite side surfaces of the upper frame <NUM>.

A plurality of fitting portions <NUM> may protrude from the upper surface of the upper frame <NUM>. Here, the fitting portions <NUM> may be formed on an upper portion of the surface where the fixed contact arm <NUM> is not exposed. When the arc cover <NUM> is coupled to the upper frame <NUM>, a side portion of the arc cover <NUM> may be fitted into the fitting portions <NUM>.

The arc cover <NUM> is disposed. The arc cover <NUM> may be made of an insulating material such as a synthetic resin material. The arc cover <NUM> may have an open lower surface and define an accommodation space therein.

The crossbar <NUM> and a movable contact arm may operate with being accommodated in the accommodation space of the arc cover <NUM>.

A trip button hole <NUM> may be formed through an upper surface of the arc cover <NUM>. A head of the crossbar <NUM> may be exposed through the trip button hole <NUM> to perform a trip operation.

A plurality of vent holes <NUM> may be formed through a side surface of the arc cover <NUM>.

The third coupling part <NUM> protrudes from one side surface of the arc cover <NUM>. The third coupling part <NUM> has a predetermined length (thickness) from a lower end portion of the arc cover <NUM>. The third coupling part <NUM> does not extend to an upper end portion of the arc cover <NUM>. In other words, the third coupling part <NUM> is formed on only a portion of the arc cover <NUM> in the vertical lengthwise direction, without being formed along an entire length of the arc cover <NUM>. That is, the length (thickness) of the third coupling part <NUM> is shorter than a length (height) of the arc cover <NUM>.

A third fastening hole <NUM> may be formed through the third coupling part <NUM> in the vertical direction (in the up and down direction). The fastening member <NUM> may be coupled to the third fastening hole <NUM>.

The third coupling part <NUM> and the third fastening hole <NUM> may be formed at each of both side portions (both end portions) on one surface of the arc cover <NUM>. At this time, the third coupling parts <NUM> and the third fastening holes <NUM> formed on the both side portions may be symmetrical with each other.

The third coupling parts <NUM> and the third fastening holes <NUM> may be formed respectively on both side surfaces of the arc cover <NUM> that are symmetrical with each other. At this time, the third coupling parts <NUM> and the third fastening holes <NUM> formed on the both side portions may be symmetrical with each other. That is, the third coupling parts <NUM> and the third fastening holes <NUM> may be formed as pairs on both opposite side surfaces of the arc cover <NUM>, respectively.

The third coupling part <NUM> and the third fastening hole <NUM> may be formed to communicate with the second coupling part <NUM> and the second fastening hole <NUM>. That is, they may be formed on a surface in the same direction.

The fastening member <NUM> such as a screw and a nut is provided. The fastening member <NUM> is coupled through the first fastening hole <NUM>, the second fastening hole <NUM>, and the third fastening hole <NUM>. Accordingly, the lower frame <NUM>, the upper frame <NUM>, and the arc cover <NUM> can be fastened by a single operation. In addition, as the arc cover <NUM> is integrally coupled to the upper frame <NUM> and the lower frame <NUM>, such coupling can be stably maintained without separation even if an arc is frequently generated.

In order to easily couple the fastening member <NUM>, a screw member <NUM> may be configured as an insert nut. The screw member <NUM> may be inserted into the first coupling part <NUM> of the lower frame <NUM>.

An auxiliary fastening member <NUM> such as a screw may be provided. The auxiliary fastening member <NUM> may be coupled through the first auxiliary fastening hole <NUM> and the second auxiliary fastening hole <NUM>. Since the upper frame <NUM> and the lower frame <NUM> are additionally coupled by the auxiliary fastening member <NUM>, the coupling force between the upper frame <NUM> and the lower frame <NUM> can further be increased.

<FIG> is a partial lateral view in a direction B in <FIG>, and is a partial cross-sectional view taken along the line C-C. <FIG> is a disassembled perspective view illustrating an arc cover and a top cover.

A top cover <NUM> may be provided. The top cover <NUM> may be coupled to an upper surface of the arc cover <NUM>.

A button hole <NUM> connected to the trip button hole <NUM> may be formed through the top cover <NUM>. The head of the crossbar <NUM> may be exposed through the button hole <NUM> to perform a trip operation.

Cover fastening holes <NUM> may be formed through the top cover <NUM>. Positions at which the cover fastening holes <NUM> are formed may be portions where phases are in contact with the top cover <NUM>.

Inter-phase insulating grooves <NUM> may be formed in the arc cover <NUM>. The inter-phase insulating grooves <NUM> and the cover fastening holes <NUM> may be disposed to communicate with each other. The inter-phase insulating grooves <NUM> may be stepped.

Claim 1:
An electromagnetic contactor comprising:
a lower frame (<NUM>);
an upper frame (<NUM>) coupled to an upper portion of the lower frame (<NUM>); and
an arc cover (<NUM>) coupled to an upper portion of the upper frame (<NUM>);
wherein a first coupling part (<NUM>) protrudes from one surface of the lower frame (<NUM>) such that a fastening member (<NUM>) is coupled,
a second coupling part (<NUM>) protrudes from one surface of the upper frame (<NUM>) and is connected to the first coupling part (<NUM>), such that the fastening member (<NUM>) is fastened, and
a third coupling part (<NUM>) protrudes from one surface of the arc cover (<NUM>) and is connected to the second coupling part (<NUM>), such that the fastening member (<NUM>) is fastened, and
wherein the fastening member (<NUM>) is coupled through the first coupling part (<NUM>), the second coupling part (<NUM>), and the third coupling part (<NUM>),
characterized in that
the first coupling part (<NUM>) has a predetermined length from an upper end portion of the lower frame (<NUM>), and is shorter than a length of the lower frame (<NUM>),
wherein the second coupling part (<NUM>) has a length from an upper end portion to a lower end portion of the upper frame (<NUM>),
wherein the third coupling part (<NUM>) has a predetermined length from a lower end portion of the arc cover (<NUM>) and is shorter than a length of the arc cover (<NUM>),
characterised in that
a first auxiliary fastening hole (<NUM>) is formed through the first coupling part (<NUM>), a second auxiliary fastening hole (<NUM>) is formed through the second coupling part (<NUM>), and an auxiliary fastening member (<NUM>) is provided to be coupled through the first auxiliary fastening hole (<NUM>) and the second auxiliary fastening hole (<NUM>).