JP6213035B2 - Magnetic contactor - Google Patents

Description

  The present invention relates to an electromagnetic contactor of b-contact specification applied to a dynamic brake of a DC motor, and more particularly to a contact structure of a stationary contact mounted on the electromagnetic contactor.

  First, the contact unit assembly structure of the conventional example (conventional example 1 and conventional example 2) for the DC electromagnetic contactor equipped with the b contact specification fixed contactor is shown in FIGS. 2, 3, 4 and 5, respectively. (For example, refer to Patent Document 1).

Conventional example 1:
2 (a) to 2 (c), 1 is a frame of a contact unit (resin molded product) combined on an electromagnet unit (lower unit) (not shown), and 1a is formed at both ends of the contact unit frame 1. Terminal pedestals on the power supply side and load side, 1b is a pole interval wall erected on both sides of the terminal pedestal 1a of each pole, 1c is an arc extinguishing chamber cover, 2 is a b contact specification fixed contact, 3 is a movable electromagnet unit A contact holder 4 connected to an iron core (not shown) and driven to the open / close position, 4 is held by the contact holder 3, and is a bridge-shaped movable contact 5 disposed opposite to the pair of fixed contacts 2. A terminal screw 6 is a rod-shaped permanent magnet for arc driving arranged on the arc-extinguishing chamber side of the contact unit frame 1, and 7 is a magnetic pole plate that is connected to both ends of the permanent magnet 6 and is erected on both sides of the fixed contact 2. is there.

  Here, as shown in FIG. 2 (c), the fixed contact 2 of the b contact specification stands in a substantially C shape from the terminal plate 2a and the rear end portion of the terminal plate 2a, and its tip is U-shaped. And a fixed contact 2d joined to the tip 2c of the contact base 2b so as to face the contact 4a of the bridge-shaped movable contact 4, and the contact base 2b and the contact 2d are respectively terminal boards. 2a, brazed to the tip 2c of the contact base 2c. Note that a square contact is generally adopted as the contact 2d.

  Further, the contact base 2b has a side edge notch portion 2e formed by recessing one side edge so as to narrow the plate width between the mounting base portion and the tip end portion 2c. As will be described later, the portion 2e forms an extension drive of an arc (DC arc discharge) generated between fixed and movable contacts, and a gas vent passage 8 (see FIG. 2B) for discharging the arc gas to the outside of the frame. Furthermore, a heat-resistant insulating cover 2f is attached to the upright conductor portion of the contact base 2b to prevent contact between the contact conductor and the arc. FIG. 3 is a side view of the contact unit assembly.

Conventional example 2:
Next, regarding the b contact specification fixed contact 2 mounted on the contact unit of the electromagnetic contactor, the assembly structure of the contact unit of the conventional example 2 having a shape different from the conventional example 1 and the shape of the fixed contact are shown in FIG. That is, as shown in FIGS. 4A and 4B, the stationary contact 2 mounted on the contact unit of the conventional example 2 is a Z-shaped body in which the terminal portion and the contact base are integrated. As described above, the flat terminal portion 2a placed on the terminal pedestal 1a (see FIG. 2 (a)) of the contact unit frame described above, and the contacts extending in an L shape from the rear end of the terminal portion 2a. It comprises a base 2b and a fixed contact 2d that is joined to the tip 2c of the terminal base 2 and faces the contact 4a of the movable contact 4, and the contact base 2b has a contact base 2b as in the prior art 1 described above. A side edge notch 2e is formed between the upright base and the tip 2c to form a contact unit An arc gas vent passage 8 (see FIG. 4 (a)) that leads to the outside of the frame 1 (see FIG. 2 (a)) is secured, and an insulating cover 2f is attached to the standing part of the contact base 2b. Yes.

  In this way, the fixed contact 2 has a structure in which the terminal plate of the conventional example 1 (see FIGS. 2 and 3) and the C-shaped terminal block are combined, and the Z-shaped integrated structure of the conventional example 2 (see FIGS. 4 and 5). By changing the external dimensions of the contact unit assembly, that is, the dimensions a1, b1, c1 of the dimensions shown in the drawing of FIG. 3 to the dimensions a2 (a2) of the dimensions shown in the drawing of FIG. <A1), b2 (b2 <b1), c2 (c2 <c1) can be reduced and the electromagnetic contactor can be configured in a small size.

JP 2012-129159 A

  As described above, the Z-shaped fixed contact 2 (conventional example 2) shown in FIGS. 4 and 5 is used for the b contact specification fixed contact 2 mounted on the contact unit frame 1 to provide electromagnetic contact. While there is an advantage that the device can be downsized, the following problems are newly derived from the arc extinction of the arc (DC arc discharge) generated between the fixed and movable contacts when the current is interrupted.

  That is, the Lorentz force f by the magnetic drive unit composed of the permanent magnet 6 and the magnetic pole plate 7 described in FIG. 2 acts on the arc generated between the fixed and movable contacts by the opening operation of the movable contact. It is driven in the direction of the solid arrow shown.

  In this case, in the stationary contact 2 of the conventional example 1 shown in FIG. 6A, the tip 2c is folded back in a U shape toward the outside of the contact unit, and further, the tip facing the upright conductor of the contact base 2b. The corner of the corner is chamfered as indicated by 2c-1 in the figure.

  Thus, the leg of the arc generated between the fixed and movable contacts as shown in the figure and magnetically driven (Lorentz force) toward the outside of the contact unit extends from the point A on the surface of the contact 2d to the corner of the contact tip 2c. It quickly shifts to the B point at the corner. In addition, the leg | foot (arcing point) of the arc produced between the square contacts has the property of shifting to the edge portion of the contact periphery where the electric field concentrates.

  Therefore, the arc transferred to the point B is not obstructed by the contact stand 2b standing and standing in front of the arc, and the dotted line shown in the drawing toward the space of the side edge notch 2e formed on the standing side edge portion of the contact stand 2b. The arc gas that extends in the direction of the arrow P and is generated in the arc extinguishing chamber is released to the outside of the contact unit frame through the gas release passage 8 of the contact unit assembly shown in FIG.

  On the other hand, in the Z-shaped fixed contact 2 of the conventional example 2 shown in FIG. 6B, the tip 2c of the contact base 2b is not folded back like the conventional example 1, but the tip 2c faces the inside of the arc-extinguishing chamber, contrary to the conventional example 1.

  Therefore, in the fixed contact 2 of the conventional example 2 having the Z-shape, the arc generated between the fixed and movable contacts is formed from the surface A of the contact 2a to the rear end corner of the contact tip 2c. Similar to the conventional example 1 in FIG. 6A, the contact point of the contact is obtained by shifting to the point B of the notched corner (the corner of the tip 2c by the side edge notch 2e in FIG. 4B). The arc and arc gas are designed to extend and discharge toward the side edge notch 2e of the contact base 2b while avoiding unnecessary interference with 2b.

  By the way, when the inventors observed the movement of the arc generated at the fixed contact 2d by the high speed camera in the current interruption repeated test, the foot of the arc (arcing point) generated between the fixed and movable contacts is the same as that of the fixed contact 2d. There is a frequent occurrence of a phenomenon that the point A is not transferred to the notched corner B point of the contact tip 2c, but is shifted to the point C (corner edge of the fixed contact 2d) and stagnated at this position. It has been confirmed. In addition, since the contact base 2b is standing and confronting in front of the point C shown in the figure, it receives a magnetic driving force (Lorentz force) and receives a magnetic driving force (Lorentz force) from the point A of the fixed contact 2d to the corner C of the same fixed contact 2d. The arc that has moved to the point and stagnated at this position, the contact stand 2b of the contact that stands in front of it becomes an obstacle, the arc length is not sufficiently extended, and the arc stagnated state continues. The arc gas generated in the arc peripheral area is not smoothly discharged to the outside of the unit because the front contact block 2c becomes an obstacle. For this reason, the fixed contact 2d is quickly consumed locally by the arc heat, and the arc extinguishing and interrupting functions are not sufficiently exhibited.

  The present invention has been made in view of the above points, and its object is to solve the above-mentioned problems and prevent arc stagnation occurring between fixed and movable contacts, so as to improve arc-extinguishing and shut-off properties. An object of the present invention is to provide an electromagnetic contactor having an improved contact shape of a fixed contact of the specification.

In order to achieve the above object, according to the present invention, there is provided an electromagnetic contactor having a b contact specification fixed contact on a terminal base of a contact unit frame facing a bridge-shaped movable contact. The fixed contact of the contact specification includes a flat terminal portion held on the terminal base, a contact base extending in an L shape from the rear end of the terminal portion, and a fixed contact at the tip of the terminal base. And a gas vent passage that leads to the outside of the unit frame by cutting out one side edge of the plate surface in a concave shape between the standing base portion and the tip portion of the contact base. In what
The shape of the fixed contact joined to the terminal block tip of the fixed contact is formed in a substantially triangular shape with the tip tapered toward the gas vent passage (Claim 1).

Further, in the electromagnetic contactor having the above configuration, a heat-resistant insulating cover is attached along the upright portion of the contact base (claim 2).
Furthermore, a magnetic plate combined with an arc driving magnet is erected on both the left and right sides of the fixed contact (Claim 3).

  According to the fixed contact of the b-contact specification having the above-described configuration, an arc generated between the fixed and movable contacts at the time of the current interrupting operation is a substantial electric field strength that acts on the legs of the arc generated on the surface of the fixed contact. It can be guided to the tapered end side of the triangle and can be quickly transferred from here to the notch corner of the contact tip corresponding to point B in FIG. 6b.

  As a result, the fixed contact with the arc that is extended due to local wear of the fixed contact and the magnetic driving force due to the continuous stagnation of the arc, which has been a problem in the b contact specification fixed contact (conventional example 2) By avoiding unnecessary interference with the contact table of the child, high arc extinguishing performance can be achieved against the arc generated between the fixed and movable contacts, and the interruption performance of the magnetic contactor can be improved.

FIG. 2 is a structural diagram of a stationary contact having a b contact specification according to an embodiment of the present invention, wherein (a) and (b) are external perspective views of the stationary contact viewed from different directions. It is a block diagram of the electromagnetic contactor concerning the prior art example 1, Comprising: (a) is sectional drawing of the whole contact unit, (b) is a perspective view of the contact unit assembly in (a), (c) is a fixed contactor FIG. It is a front view of the contact unit assembly corresponding to FIG.2 (b). It is a block diagram of the contact unit concerning the prior art example 2, Comprising: (a) A perspective view of a contact unit assembly, (c) is an external perspective view of a stationary contact. It is a front view of the contact unit assembly corresponding to Fig.4 (a). It is explanatory drawing of the arc transition in the stationary contact of the prior art example 1 and the prior art example 2, Comprising: (a), (b) is explanatory drawing corresponding to FIG. 2 (a) and FIG.4 (b), respectively.

  Embodiments of the present invention will be described below based on the examples shown in FIGS. 1 (a) and 1 (b). In addition, in the figure of an Example, the same code | symbol is attached | subjected to the member corresponding to FIG.4 (b) and FIG.6 (b), and the description is abbreviate | omitted.

  That is, the b contact specification fixed contact according to this embodiment shown in FIG. 1 has a Z-shaped integral structure basically similar to the fixed contact 2 of the conventional example 2 shown in FIG. Is joined to the lower surface of the tip 2c of the contact base 2b that rises L-shaped from the terminal 2a. Here, the shape (contour shape) of the fixed contact 2d in the conventional example 2 is a square (square), whereas in the embodiment of FIG. Further, the tip of the triangular taper is joined to the tip 2c of the terminal block in a posture in which the tip of the triangle is directed to the side edge notch 2e of the contact block 2b. Further, the contact base 2b has a heat-resistant insulating cover 2f attached to the contact conductors between the base portion and the tip portion 2c. Further, although not shown in FIG. 1, an arc magnetic drive unit comprising permanent magnets 6 and magnetic pole plates 7 similar to that described in FIG. 2A is provided on the arc extinguishing chamber side of the contact unit.

  With the above configuration, with respect to the behavior of the arc generated between the fixed and movable contacts during the current interrupting operation, the arc foot generated at the point A on the surface of the fixed contact 2d receives a Lorentz force from the magnetic drive unit and has a triangular shape. It is guided to the tapering tip side of the fixed contact 2d, and from there, it quickly shifts to the point C of the corner corner of the contact tip 2c where the electric field concentrates further.

  As a result, the phenomenon in which the arc continuously stagnates at the peripheral corner portion (point C in FIG. 6B) of the fixed contact, which has been regarded as a problem in the contactor structure of the conventional example 2 described in FIG. 6B, is solved. Thus, it is possible to provide an electromagnetic contactor with high breaking performance and high reliability by effectively avoiding arc extinguishing performance and local wear of the fixed contact.

DESCRIPTION OF SYMBOLS 1 Contact unit frame 2 B contact specification fixed contact 2a Terminal part 2b L-shaped contact stand 2c Tip part 2d Fixed contact 2e Side edge notch 2f Insulation cover 4 Bridge-shaped movable contact 6 Permanent magnet of arc drive unit 7 Pole plate 8 Gas vent passage

Claims (3)

An electromagnetic contactor provided with a b contact specification fixed contact on the terminal base of the contact unit frame facing the bridge-shaped movable contact, and the b contact specification fixed contact held on the terminal base It has a configuration in which a flat terminal portion, a contact stand extending in an L shape from the rear end of the terminal portion, and a fixed contact facing the contact of the movable contact are joined to the tip of the terminal block. In addition, between the standing base portion and the tip portion of the contact base, one side edge of the plate surface is notched in a concave shape so as to secure a gas vent passage that leads to the outside of the frame.
The electromagnetic contactor characterized in that the shape of the fixed contact joined to the terminal block tip of the fixed contact is formed in a substantially triangular shape with the tip tapered toward the gas vent passage.   The electromagnetic contactor according to claim 1, wherein a heat-resistant insulating cover is attached along an upright portion of the contact base.   3. The electromagnetic contactor according to claim 1, wherein magnetic plates combined with arc driving magnets are provided upright on both the left and right sides of the stationary contact.