JPH0142253Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an electromagnetic contactor, and more particularly to an electromagnetic contactor that covers a main circuit contact of the electromagnetic contactor and extinguishes an arc generated when the contact is opened.

An electromagnetic contactor is a device that opens and closes main circuit contacts to control the opening and closing of electric circuits such as electric motors, and this device is generally provided with an arc box that covers the contacts for danger prevention and dust prevention.

FIG. 1 shows the main structure of a conventional electromagnetic contactor including an arc box structure, and a fixed core (not shown) is equipped with an operating coil.
By excitation of the operating coil, a movable core (not shown) is brought into contact with and separated from the fixed core to open and close the main circuit contacts.

That is, a cross bar 10 is fixed to the movable core, and the cross bar 10 is provided to be movable up and down as the movable core moves toward and away from the fixed core. A movable contactor 12 is arranged on the crossbar 10. The movable contact 12 is connected to the crossbar 10
It is formed by a movable contact piece 16 that is slidably supported on the upper end of the movable contact piece 16 via a spring 14, and a movable contact 18 for opening and closing the main circuit provided at the tip of the movable contact piece 16.

On the other hand, a fixed contact 20 is disposed at a lower position opposite to the movable contact 12. That is, a terminal plate 24 for attaching an external wiring material is fixed to an insulating base 22 of the electromagnetic contactor, and a base portion of a substantially U-shaped fixed contact piece 26 is fixed to the terminal plate 24 with a screw. A fixed contact 28 is fixed on the upper surface of the fixed contact piece 26 so as to face the movable contact 18. The fixed contact piece 26 and the fixed contact 28 form a fixed contact 20, and the movable contact 28 is fixed to the upper surface of the fixed contact piece 26. It is arranged opposite to the child 12. Therefore, as the movable iron core approaches and separates from the fixed iron core, the crossbar 10 moves up and down, and the main circuit contacts, that is, both movable and fixed contacts 1
8 and 28 are opened and closed.

Both the movable and fixed contacts 12, 20 are covered with an arc box 30 for safety and dust protection, and the arc box 30 is screwed and fixed to the base 22 of the electromagnetic contactor. A guide hole 32 on which the cross bar 10 slides is formed in the center of the arc box 30, and vertical movement of the cross bar 10 as the movable core moves toward and away from the fixed core slides into the guide hole 32. This prevents the crossbar 10 from tilting.

The arc box 30 is made of a heat-resistant material such as glass-filled thermosetting resin or porcelain to prevent burnout due to arc heat generated when the main circuit contacts are opened, that is, when both the movable and fixed contacts 18 and 20 are opened. It is formed by. The arc box 30 is provided with an arc extinguishing device to prevent the contacts from being burnt out due to the arc heat. This arc extinguishing device is formed of a grid 34 and a flow plate 36, which are each caulked and fixed at one end to the top wall of the arc box 30 and arranged adjacent to each other, and the tip of the grid 34 is located above the fixed contact piece 26. On the other hand, the distal end of the flow plate 36 extends near the movable contact piece 16 when the contact is in the open state. As a result, the arc generated when the main circuit contacts open moves from the movable contact 18 and the fixed contact 28 to the protrusion 42 of the flow plate 36 and the upper end of the fixed contact piece 26, and is further drawn to the grid 34 and separated. The arc is extinguished.

However, in conventional devices of this type, the arc box 30 is made of a glass-filled thermosetting resin or a material such as porcelain, and is therefore very hard. The cross bar 10 rubs against each other in the guide hole 32 described above, and as a result, the sliding wear of the cross bar 10 is extremely severe, resulting in drawbacks such as the cross bar 10 rattling and tilting.

The present invention has been devised in view of the above-mentioned conventional problems, and its purpose is to provide an electromagnetic contactor in which almost no sliding wear of the crossbar occurs when the crossbar moves up and down.

In order to achieve the above object, the present invention has a structure in which a movable core is brought into contact with and separated from a fixed core by excitation of an operating coil attached to a fixed core, and a crossbar 10 attached to a movable core is interlocked with the crossbar 10 provided on the crossbar 10. In an electromagnetic contactor that controls the opening and closing of an electric circuit by bringing a movable contact 18 into and out of contact with a fixed contact 28, an arc box 30 that covers at least the movable contact 18 and the fixed contact 28, and an arc box 30 formed on a wall of the arc box 30 and a The guide hole 32 that constitutes the movement path of the cross bar 10 and the fitting step 38 formed on the inner wall surface of the guide hole 32 are rotated or misaligned in a plane direction perpendicular to the path direction of the guide hole 32. a guide bush 40 formed of a material softer than the cross bar 10, which is fitted to the arc box 30 and forms a sliding surface for the cross bar 10; A shifting plate 36 extends near the movable contact 18 in the open state to extinguish the arc when the contact is opened, and engages with the guide bush 40 to move the guide bush 40 in the direction of the path of the guide hole 32. It is characterized in that it includes a shifting plate 36 that prevents positional displacement.

Hereinafter, preferred embodiments of the present invention will be described based on the drawings.

FIG. 2 shows the configuration of the arc box structure of the electromagnetic contactor according to the present invention, and the same members as in the conventional device are given the same reference numerals and their explanations will be omitted.

A feature of the present invention is that a guide bush for sliding the crossbar is installed in the guide hole of the arcbox to prevent sliding wear between the crossbar and the arcbox.

In this embodiment, as shown in FIG. 2, a fitting step 38 for fitting the bushing is formed in the guide hole 32 of the arc box 30, and the step 38 is made of a material softer than the cross bar 10, such as thermoplastic resin. A guide bush 40 molded from is fitted and mounted.
In this embodiment, as shown in FIG. 3, the guide bush 40 is formed in a square shape, and the peripheral wall of the fitting step 38 is formed in a square shape corresponding to the bush 40. Free rotation within the portion 38 is restricted. The lower surface of the guide bush 40 is engaged with and held by the flow plate 36, and the guide bush 40 is connected to the guide hole 32 of the arc box 30.
It is fixedly attached to. That is, as shown in FIG. 3, protrusions 42 extending near the aforementioned movable contact piece 16 are bent at both ends of the flow plate 36, and these protrusions 42 serve as bridges. Part 4
It is bridged by 4. An engagement recess 46 is formed in the center of the bridging portion 44 and holds the lower surface and both side surfaces of the guide bush 40 in contact with each other, and the guide bush 40 is engaged and held in the engagement recess 46.

Note that the bottom surface of the engagement recess of the bridging portion 44 is opened so as to pass through the cross bar 10.

In this way, the guide bush 40 is held by the fitting cutout 38 and the shifting plate 36 without providing any new members.

The size of the insertion hole 48 of the guide bush 40 is designed to be smaller than the guide hole 32 of the arc box 30, thereby preventing the cross bar 10 from coming into direct contact with the wall of the guide hole.

Therefore, the cross bar 10 moves up and down without sliding on the arc box.
Since the cross bar 10 is guided by sliding with the guide bush 40 which is softer than the cross bar 10, abnormal wear of the cross bar 10 is prevented, and rattling and tilting of the cross bar 10 is reliably prevented.

As explained above, according to the present invention, the vertical movement of the crossbar as the movable iron core approaches and separates from the fixed iron core is performed without contacting the hard arc box, and this vertical movement is softer than the crossbar. Since this is done by sliding on the guide bush of the crossbar, abnormal wear of the crossbar can be reliably prevented, and rattling and tilting of the crossbar can be avoided.

Further, even if the guide bush is worn out, by replacing only the guide bush, rattling and tilting of the crossbar can be prevented, and the reliability of the electromagnetic contactor can be economically advantageously maintained.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of main parts showing the arc box structure of a conventional electromagnetic contactor, FIG. 2 is a block diagram of main parts showing the arc box structure of a magnetic contactor according to the present invention,
3 is a perspective view showing the engagement relationship between the guide bush and the flow plate shown in FIG. 2. FIG. In each figure, the same members are given the same reference numerals, 10 is a crossbar, 18 is a movable contact, 28 is a fixed contact, 3
0 is an arc box, 32 is a guide hole, 34 is a grid, 36 is a flow plate, and 40 is a guide bush.

Claims (1)

[Claims for Utility Model Registration] The movable core is moved toward and away from the fixed core by excitation of the operating coil attached to the fixed core, and the crossbar 10 attached to the movable core is interlocked with the crossbar 10.
In an electromagnetic contactor that controls opening and closing of an electric circuit by connecting and separating a movable contact 18 provided to a fixed contact 28, at least the movable contact 18 and the fixed contact 2
an arc box 30 covering the cross bar 8; and a guide hole 32 formed in the wall of the arc box 30 and forming a movement path of the cross bar 10.
and is fitted into a fitting step portion 38 formed on the inner wall surface of the guide hole 32 so as not to cause rotation or positional displacement in a plane direction perpendicular to the path direction of the guide hole 32,
and constitutes a sliding surface for the crossbar 10.
A guide bush 40 formed of a material softer than the crossbar 10 is fixed to the wall of the arc box 30 and extends to a position near the movable contact 18 when both contacts are open, and when the contact is opened. An electromagnetic contact characterized by comprising: a flow plate 36 for extinguishing an arc, which engages with the guide bush 40 and prevents the guide bush 40 from shifting in the direction of the path of the guide hole 32. Arc box structure of the vessel.