JPH0145063Y2 - - Google Patents

Description

[Detailed description of the invention] [Technical field to which the invention pertains] The present invention relates to an auxiliary contact device having an auxiliary contact that operates in conjunction with a movable contact of a main body of an electromagnetic contactor.

Magnetic contactors are often used to start and stop motors that are frequently opened and closed, but these magnetic contactors often require auxiliary contacts in addition to movable contacts, and the number of these contacts cannot be controlled. Since it differs depending on the target, it is desired that auxiliary contacts be easily added and replaced. For this purpose, the auxiliary contact device is formed separately from the electromagnetic contactor main body and is detachably attached to the electromagnetic contactor main body.

[Prior art and its problems]

This type of conventional device is shown in FIGS. 1 and 2, and FIG. 1 is a side sectional view of the auxiliary contact device.
FIG. 2 is an assembled exploded view of the electromagnetic contactor body and the auxiliary contact device.

The auxiliary contact device 4 for an electromagnetic contactor includes fixed contacts 5 and 6 provided in pairs on the upper and lower sides, bridge-type movable contacts 7 and 8 provided corresponding to the fixed contacts 5 and 6, respectively. Movable contact support 9, base 10a and cover 10 that house these
Case 10 consisting of b is the main component.
Each of the fixed contacts 5 and 6 is held by being fitted into a recess formed in the base 10a of the case 10, and a fixed contact is attached to one end of each, and terminal screws 11 and 12 are provided at the other end. . Movable contacts 7, 8 with movable contacts attached to each fixed contact
is supported by a movable contact support 9 as follows. In other words, the movable contact support 9 made of insulating material is
It is placed in the empty space of the base 10a of the case 10, and on one side thereof is provided with a columnar projection 9a for connecting to the movable contact support in the electromagnetic contactor main body or the movable contact support in the preceding auxiliary contact unit, A hole is provided on the opposite surface of the projection 9a into which a columnar projection of the next stage of movable contact support having the same dimensions as the projection 9a is fitted. Further, the body of the movable contact support 9 is provided with rectangular through holes for attaching the movable contacts 7 and 8. Movable contacts 7 and 8 are inserted into the lower and upper sides of this through hole, respectively, with their contacts protruding from both sides of the body.
A coil spring 13 is compressed and inserted between the movable contacts 7 and 8 to reduce the impact when the contacts of the movable contacts 7 and 8 collide with the contacts of the movable contacts. Case 1
0 is provided with a window 10c for passing through the columnar projection of the movable contact support of the next stage and a connecting screw through hole 10d. In order to additionally attach an auxiliary contact device to the electromagnetic contactor body 1, as shown in FIG. A window 1b for connecting to the contact support and a screw hole 1c for mounting an auxiliary contact device are provided.

To attach the auxiliary contact device 4 to the electromagnetic contactor body 1, insert the columnar projection 9a of the movable contact support 9 of the auxiliary contact device 4 into the window 1b of the electromagnetic contactor body 1 as shown by the arrow in FIG. At the same time, the screw 14 is passed through the screw through hole 10d of the auxiliary contact device 4 and screwed into the screw hole 1c of the electromagnetic contactor body 1. Note that numeral 2 is a terminal of the main contactor.

In addition, as another conventional device, an auxiliary contact device 4 is provided on both sides 1a of the electromagnetic contactor main body 1 as shown in FIG.
It is also known that a hook-shaped engagement protrusion 15 provided with the auxiliary contact device 4 engages with a window 1d provided in the window 1d, thereby simplifying the installation of the auxiliary contact device 4.

By the way, in such an auxiliary contact device 4, wear powder is generated due to friction between the movable contact support 9 and the case 10, and friction between the movable contacts 7 and 8 and the movable contact support 9. There is a drawback that abrasion powder adheres to the contacts of each contact, resulting in poor contact between the contacts. In particular, since the auxiliary contact circuit is often connected to a low-voltage control power supply circuit, the influence of wear particles is large. In addition, in order to reduce the contact resistance between the fixed contact and the movable contact in an auxiliary contact device, it is necessary to apply sufficient contact pressure through a coil spring, but when a large number of auxiliary contact devices are installed, the movable contact support moves. Since the contact pressure is attenuated, there is a problem in that sufficient contact pressure cannot be obtained and the number of auxiliary contact devices that can be installed is limited.

Movable contact support 9 and case 10 of auxiliary contact device
It is also known to use a reed switch connected to the terminal of the auxiliary contact in order to eliminate the influence of abrasion powder caused by friction between the contact and the auxiliary contact. By the way, as shown in the relationship between the fixed contact 6 and the movable contact 8 and the fixed contact 5 and the movable contact 7, the auxiliary contact device of an electromagnetic relay is generally equipped with a normally open contact and a normally closed contact. During the switching operation of the main unit (switching from the return state to the closing state and from the closing state to the return state)
It is desirable that the contacts do not close at the same time. For this reason, if normally open contacts and normally closed contacts are configured using reed switches, there will be no problem as long as the distance between each reed switch is wide, but as with an electromagnetic contactor, the movable contact has a large amount of movement. If the reed switch cannot be closed, the gap between the reed switches cannot be widened, and this has the disadvantage that the normally open contact and the normally closed contact close simultaneously during the switching operation of the electromagnetic switch.

[Purpose of invention]

An object of the present invention is to provide an auxiliary contact device for an electromagnetic contactor that eliminates the drawbacks of conventional devices and can operate reliably without being affected by wear particles.

[Key points of the idea]

The main points of the present invention include an auxiliary contact case attached to the electromagnetic contactor main body, a movable rod housed in the auxiliary contact case and connected to the movable contact of the electromagnetic contactor main body and having a permanent magnet fixed thereto, and the auxiliary contact case. The permanent magnets are connected to the terminals of at least two sets of auxiliary contacts fixed to the contact case, and
In an auxiliary contact device for an electromagnetic contactor equipped with a reed switch that operates in response to separation, the permanent magnet is magnetized parallel to the lead piece of the reed switch, with one side magnetized as an N pole and the other side as an S pole, and facing the reed switch. The point is that it is made of ferrite material with a ferromagnetic plate attached to the opposite side.
By using the reed switch in this manner, the influence of wear particles can be eliminated, and the magnetic flux of the permanent magnet can be efficiently transferred to the reed switch from inexpensive ferrite material, resulting in stable operation.

[Example of idea]

4, 5A and 5B respectively show an auxiliary contact device having a normally open contact and a normally closed contact using a reed switch, FIG. 4 is a block diagram thereof, and FIGS. 5A and 5B are FIG. 6 is an explanatory diagram of each operation.

In the figure, the auxiliary contact device 4 is shown again, and this auxiliary contact device 4 has a case 1 consisting of a base 10a and a cover 10b forming an outer frame of the auxiliary contact device.
0. A pair of upper and lower auxiliary contact terminals 21 and 2 that are respectively fitted into the grooves formed in the base 10a.
2. A reed switch 23 with lead pieces connected to the terminals 21, 21, respectively; a reed switch 24, with lead pieces connected to the terminals 22, 22, respectively;
The main components are a permanent magnet 25 for opening and closing the reed switches 23 and 24, and a movable rod 91 to which the permanent magnet 25 is fixed and connected to a movable contact support of the electromagnetic contactor body.

Each pair of the terminals 21, 21 is fitted into a groove formed in the base 10a with one end facing each other, and one end of each pair is connected to a lead piece of each reed switch 23, 24, In addition, terminal screws 1 are attached to the other ends of the terminals 21 and 22.
1 and 12 are provided. reed switch 2
3 and 24 are arranged in the empty space of the base 10a of the case 10, and the lead pieces thereof are connected to the terminals 21 and 24 as already mentioned.
22, respectively. Further, a movable rod 91 is placed in a space in the base 10a of the case 10 so as to be movable up and down. This movable rod 91 is made of the same insulating material as the movable contact support 9 of the conventional auxiliary contact device 4 and is formed into a substantially prismatic shape, and has one side attached to the movable contact support of the electromagnetic contactor body or the movable contact support of the preceding auxiliary contact device. A columnar projection 91a connected to the rod 91 is provided, and projects outward from a window 10c provided in the base 10a. The opposite side of the protrusion 91a is made thicker, and a hole 91b is provided in that surface into which a columnar protrusion 91a of the movable rod 91 of the next stage having the same size as the protrusion 91a fits through the window 10e of the cover 10b. Furthermore, a permanent magnet 25 is fixed to the body part facing one of the reed switches 24 in FIG. 4, and moves up and down in conjunction with the movement of the movable contact of the electromagnetic contactor main body. Therefore, this permanent magnet 25
is moved up and down by the movement of the movable rod 91. The case 10 has a base 10a and a cover 10b with a window 10c through which a columnar projection 91a projects or is inserted, and a screw through hole 10d for coupling with the electromagnetic contactor main body.
is provided. The main body of the electromagnetic contactor is exactly the same as the conventional one shown in FIG. 2, so a description thereof will be omitted.

To attach this auxiliary contact device 4 to the electromagnetic contactor body 1, the columnar protrusion 91a is inserted into the window 1b of the electromagnetic contactor body 1 in the same manner as the method shown in FIG. Connect it to the movable contact support and insert the coupling screw into hole 1 of the auxiliary contact device 4.
0d and screw hole 1 of the electromagnetic contactor main body 1.
Tighten the screw to c. When two auxiliary contact devices 4 are attached at the same time, the columnar protrusion 91a of the second auxiliary contact device 4 is fitted into the hole 91b of the movable rod 91 through the window 10c of the first auxiliary contact device 4, and the auxiliary contact device 4 is attached. Fasten with a connecting screw that is longer than when there is only one device.

The reed switches 23 and 24 are made of permanent magnets 25.
When the contacts approach, the contacts close and when they separate, the contacts open. Therefore, when the electromagnetic contactor main body is in the open state, the movable rod 91 is in the position shown in FIG. 5A, and the permanent magnet 25 is facing the reed switch 24. , the reed switch 24 is closed and the reed switch 23 is open. When the electromagnetic contactor main body is excited and turned on, the movable rod 91 is in the position shown in FIG. 5B, and the permanent magnet 25 is facing the reed switch 23, so the reed switch 23 is closed and the reed is closed. The switch 24 is open. In this manner, in this embodiment, the auxiliary contact device 4 having one normally open contact and one normally closed contact operates.

As mentioned above, in an auxiliary contact device having a normally open contact and a normally closed contact, it is desirable that the normally open contact and the normally closed contact do not close simultaneously during the switching operation of the electromagnetic contactor body. During the switching operation, the reed switch 24 must first be opened, and then the reed switch 23 must be closed.
The time (distance) from when the reed switch 24 opens to when the reed switch 23 closes is called the switching time (switching distance), and if the switching time cannot be taken, each reed switch closes at the same time. The time is called the overlap time.

FIGS. 6 and 7 are explanatory diagrams showing the operating states of the reed switch depending on the positions of the reed switch and the permanent magnet. FIG. 6 shows the case where there is an overlap time, and FIG. 7 shows the case where there is a switching time. In each figure, the horizontal axis x is the distance between the reed switch and the permanent magnet, and the vertical axis y is the upward movement distance of the permanent magnet.
The inside of the line connecting a21 is the magnetic field area that can be touched by each reed switch, the shaded area is the unstable magnetic field area due to hysteresis caused by the residual magnetic flux to the reed switch's reed piece, and the outside area other than these is the open magnetic field. Indicates the area.

As is clear from FIGS. 6 and 7, when the distance l between the reed switches 23, 24 and the permanent magnet 25 is constant, and the permanent magnet 25 has a large external shape and a strong magnetic force, the overlap time t _p (overlap distance l _p ) occurs (Fig. 6), and the permanent magnet 2
If the outer shape of the reed switch 5 is relatively small and has the magnetic force necessary to drive the reed switch, a switching time t _c (switching distance l _c ) can be obtained. Even in the case shown in FIG. 6, switching time can be obtained by increasing the distance l between the reed switches 23 and 24, but since the stroke of the movable part of the electromagnetic contactor is small, the length of the distance l is limited. When this distance l is constant, as shown in FIG. 7, if the outer shape of the permanent magnet 25 is made smaller, the same effect as when the distance l is made longer can be obtained. By the way, since the auxiliary contact device 4 is attached to the electromagnetic contactor body and is used in an area affected by the leakage magnetic flux of the electromagnet of the electromagnetic contactor and the magnetic flux due to the main circuit current, a reed switch is required to reduce the influence of these external magnetic fields. It is preferable to use a reed switch with a relatively large magnetizing force. Therefore, in order to drive a reed switch with a large magnetic magnetizing force and obtain a switching time, a small permanent magnet with strong magnetic force is required.Such permanent magnets include alnico or rare earth magnets. is very expensive.

Therefore, in the present invention, in order to be able to drive the reed switch using an inexpensive ferrite magnet, a permanent magnet is constructed as shown in FIG. 8. That is, in FIG. 8, 26a is a permanent magnet made of a ferrite magnet and magnetized so that one side is N pole and the other side is S pole parallel to the reed switch reed piece, and 26b is the magnetic pole face (lead) of permanent magnet 26a. This is a ferromagnetic plate made of a mild steel plate or the like that is attached to the opposite side of the switch. In this way, the permanent magnet 26a and the ferromagnetic plate 26b
FIG. 9 shows the driving principle of the reed switch 23 (24) when a magnet body 26 consisting of This is prevented by the magnetic plate 26b, so that when a magnet approaches the reed switch, the magnetic flux of the permanent magnet 26a can be efficiently flowed to the reed piece of the reed switch, thereby making it possible to drive the reed switch.

Next, FIG. 10 shows a different embodiment of the present invention,
Components in the figure that are the same as those shown in FIG. 4 are designated by the same reference numerals, and their explanation will be omitted.

In FIG. 10, 27 is the reed switch 2.
3 and 24, and is fixed to the base 10a by support pieces 28 and 29, and is a magnetic pole piece made of a mild steel plate or the like. This magnetic pole piece 27 becomes a magnetic flux path of the permanent magnet 25 when the permanent magnet 25 approaches the magnetic pole piece 27. When the magnetic pole piece 27 is placed in the middle position between the reed switches 23 and 24, the magnetic contactor main body is During the switching operation, when the permanent magnet 25 approaches the pole piece 27, most of the magnetic flux of the permanent magnet 25 flows through the pole piece 27, resulting in a switching time _tc . That is, as shown in FIG. 11, when the permanent magnet 25 descends from the illustrated position and approaches the magnetic pole piece 27 during the switching operation from the return state where the permanent magnet 25 faces the reed switch 24 to the closed state, Most of the magnetic flux of the permanent magnet 25, which had been flowing through the reed piece of the reed switch 24, flows through the magnetic pole piece 27, and the reed switch 24 is opened. At this time, a small amount of magnetic flux flows through the reed piece of the reed switch 23, but the contact is not closed and the reed switch 23 remains open. When the permanent magnet 25 further descends, most of the magnetic flux of the permanent magnet 25 that has flowed through the magnetic pole piece 27 flows into the reed piece of the reed switch 23, and the reed switch 23 is closed. Even during the switching operation of the electromagnetic contactor main body from the closing state to the returning state, the switching time t _c is obtained for the same reason as described above.

[Effect of idea]

According to the present invention described above, the following effects can be obtained. That is, since the auxiliary contact device is opened and closed by the contacts of the reed switch enclosed in the glass tube, it is not affected by abrasion powder caused by friction between the movable rod and the case of the auxiliary contact device.

A ferrite magnet can be used as the permanent magnet for driving the reed switch, making it possible to provide an inexpensive auxiliary contact device.

The switching time can be obtained simply by placing the magnetic pole piece between the reed switches, and the structure is simple and easy to assemble.

It has the following effects.

[Brief explanation of the drawing]

Figures 1 and 2 are a side cross-sectional view of an auxiliary contact device of a conventional device and an assembled exploded view of the electromagnetic contactor body and the auxiliary contact device, respectively, and Figure 3 is a diagram showing the electromagnetic contactor body of an auxiliary contact device of a different conventional device. Developed assembly diagram of the auxiliary contact device, Figures 4, 5A, and 5B
The figures each show an auxiliary contact device having a normally open contact and a normally closed contact using a reed switch. Figures 1 and 11 are explanatory diagrams showing the operating states of the reed switch depending on the positions of the reed switch and the permanent magnet, respectively. Figure 8 is a perspective view showing an embodiment of the present invention. Figure 9 is the operating principle of Figure 8. 10 are side sectional views of an auxiliary contact device showing different embodiments of the present invention. 1: Magnetic contactor body, 4: Auxiliary contact device, 1
0: Auxiliary contact case, 21, 22: Auxiliary contact terminal, 23, 24: Reed switch, 25, 26
a: permanent magnet, 26b: ferromagnetic plate, 27: magnetic pole piece, 91: movable rod.

Claims (1)

[Claims for Utility Model Registration] 1. An auxiliary contact case attached to the electromagnetic contactor main body, a movable rod housed in the auxiliary contact case, connected to the movable contact of the electromagnetic contactor main body, and to which a permanent magnet is fixed. and an auxiliary contact device for an electromagnetic contactor, comprising a reed switch connected to terminals of at least two sets of auxiliary contacts fixed to the auxiliary contact case and operated in response to approach/departure of the permanent magnet, wherein the permanent magnet It is made of a ferrite material that is magnetized parallel to the lead piece of the reed switch, with one side magnetized as a N pole and the other side as an S pole, and a ferromagnetic plate is pasted on the opposite side to the surface facing the reed switch. Auxiliary contact device for magnetic contactors featuring features. 2 Utility Model Registration Scope of Claim 1. An auxiliary contact device for an electromagnetic contactor, characterized in that the device has a magnetic pole piece between each reed switch that serves as a magnetic path of a permanent magnet.