JPS601713A - Lead switch - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a reed switch that opens and closes magnetically.

In general, typical reed switches with sealed contacts are:
A pair of magnetic leads with contacts are enclosed in a glass container. Both leads are spaced apart at each free end;
It is enclosed in a glass container in the form of cantilever springs that overlap each other. When a magnetic field is applied from a magnetic field source, the leads come into contact and form an electrical path, and when the magnetic field is removed, they spring back to interrupt the electrical path.

In recent years, as improvements have been made to this type of reed switch, it has become possible to open and close large loads.However, with this type of reed switch, the influence of the magnetic field generated by the current flowing through the reeds acts to accelerate the deterioration of the contacts. As a result, there was a drawback that it was not possible to open or close a large load above a certain level.

The present invention not only eliminates these drawbacks.

By using the influence of the magnetic field generated by the current flowing through the leads and the electrostatic attraction force, contact deterioration is minimized.

The purpose of the present invention is to provide a reed switch capable of opening and closing a large load, and a temperature-sensitive switch having a large contact capacity consisting of a combination of the reed switch, a temperature-sensitive magnetic material, and a permanent magnet.

The configuration of the present invention basically includes the following energization. A pair of leads with contacts are enclosed in a glass container. One lead is the main magnetic lead and the other lead is functionally non-magnetic. Each free end has a contact point in the form of a mutually overlapping cantilever support and is sealed in a glass container in contact with suitable compression. The main magnetic lead has spring properties.

The stiffness is the amount that causes deflection due to magnetic attraction. Further, an auxiliary magnetic lead is fixed to the glass container or the non-magnetic lead such that the free end of the main magnetic lead faces opposite to the contact point of the non-magnetic lead with a gap therebetween. . The stiffness of the auxiliary magnetic lead is so large that there is almost no deflection due to magnetic attraction.

The gap between the free end of the main magnetic lead and the free end of the auxiliary magnetic lead is large enough to generate magnetic attraction when a magnetic field is applied.

The reed switch of the present invention is basically characterized by the above-described configuration, and the contacts are closed when no magnetic field is generated from the magnetic field source.

The main magnetic lead and the non-magnetic lead form an electrical path.

When a magnetic field is generated, the main magnetic lead and the auxiliary magnetic IJ-de are attracted, the contacts open and the electrical path is cut off.

The following two aspects of the present invention will be explained with reference to the drawings.

Generally, a typical reed switch has a structure as shown in FIG. 1, in which a pair of magnetic leads 2'2' have contacts at their free ends with an appropriate gap.

An inert gas 4 is sealed inside the glass container 3.

When a magnetic field is applied from an external magnetic field source, opposite magnetic poles are generated at the contact portions of the magnetic leads 2 and 2', and the contacts are closed. At this time, if the leads 2, 2' are connected to an external circuit having a power source 5 as shown in FIG. 2, current flows through the magnetic leads 2, 2'. When a current flows through the magnetic leads 2 and 2', 2
A magnetic field is generated in the circumferential direction of the magnetic leads 2, 2' by the applied current, and a spin magnetic moment directed in the length direction of the leads 2, 2' by the external magnetic field is caused by the magnetic field in the circumferential direction. , 2' in a spiral direction. As a result, the magnetic flux density in the length direction of the magnetic IJ-1'2.2' decreases. When the magnetic flux density in the length direction of the magnetic reed 2.degree. 2' decreases due to the applied current, the following phenomenon occurs in the reed switch.

(1) The four-turn value at which the reed switch contacts open, ie, the open value, increases in proportion to the magnitude of the energizing current.

(2) When the energizing current exceeds a certain level, when the energizing current becomes zero when the reed switch contacts open, the lead 2,
When the magnetic flux density at 2' increases, the magnetic attraction force becomes large again, and the contact closes. This repetition causes electromagnetic chattering.

For details regarding (1) and (2), please refer to the Institute of Electrical Engineers of Japan Magnetic Application Study Group Material No. AM-79-63r A Study on Contact Opening and Closing of Thermal Reed Switch (1979)
(December 21, 2013).

From the phenomenon (1), for the reed switch contacts.

The suppression due to the magnetic attraction force becomes smaller as the applied current becomes larger. As the suppression decreases, the contact resistance of the contact increases, and the heat generated at the contact increases. As the temperature rises, the damage to the contacts that occurs when they open becomes more severe. In addition, when the 1st energizing current is alternating current, if the change in the external magnetic field that opens and closes the reed switch is slower than the frequency of the alternating current, the contacts open when the 2nd energizing current reaches its maximum. That is,
For contacts, they open when the alternating current is most severe.

Next, if long electromagnetic chattering occurs when the contacts are opened due to the phenomenon (2), spot erosion occurs in the contacts, damaging the contacts.

As mentioned above, as shown in Fig. 1, the conventional reed switch 1 has a
When switching large currents, this is disadvantageous in terms of contact deterioration.

The present invention overcomes these disadvantages.

3 to 6 show various embodiments of the reed switch of the present invention. As a representative example, the operating principle of the embodiment shown in FIG. 3 will be explained. A main magnetic lead 5 and a non-magnetic lead 6 having contacts 9 and 9', respectively, are enclosed in a glass container 8. Both leads 5 and 6 are drawn out of the container so that they can be connected to an external circuit. At this time, contacts 9,9' are in contact with appropriate pressure. The magnetic lead 5 has spring properties,
The stiffness is set to a value that causes deflection due to the magnetic attraction force. An auxiliary magnetic lead 7 is fixed to the glass container 8 approximately parallel to the non-magnetic lead 6 and having a gap from the free end of the main magnetic lead 5. If the magnetic field is increased by 4, the air gap becomes bimagnetic! 7-1'517 is the size that can be sucked. The stiffness of the auxiliary magnetic lead 7 is preferably such that it hardly bends due to the magnetic attraction force. Contacts 9 and 9' are closed when no magnetic field is applied, and when a magnetic field is applied, magnetic lead 5 is attracted to magnetic lead 7 and contacts 9 and 9 are closed.
′ opens. (Hereinafter, the magnitude of the magnetic field at the time of opening will be referred to as the opening value). Further, when the magnetic field is made smaller again, contact point 9
, 9' are closed (hereinafter, the magnitude of the magnetic field at the time of closure will be referred to as the closure value). Next, the contacts 9 and 9' of these leads are closed and current flows through the leads 5 and 6. At this time, the magnetic flux density in the length direction of the main magnetic lead 5 is reduced by the applied current. This is the same as the conventional reed switch 1 shown in FIG. However, in the case of the reed switch of the present invention.

The contact is suppressed by the spring force of the magnetic reed 5 (conventional reed switches have a magnetic attraction force). and.

The force that opens the contacts is the magnetic attraction force with the magnetic lead 7 (the conventional reed switch has a spring force of the magnetic lead 1° 1'). For this reason, when the magnetic flux density in the length direction of the magnetic lead decreases due to the energizing current, the following can be said about the contacts of the IJ-type switch.

(a) The pressure applied to the contacts 9 and 9' increases in proportion to the applied current.

(b) When the applied current is alternating current, and the change in the external magnetic field is slow compared to the frequency of the alternating current, the contacts open when the applied current is at its minimum.

(c) When contacts 9 and 9' open and the current flowing becomes zero,
Since the magnetic attraction force increases and the separation force becomes stronger, electromagnetic chatter does not occur.

As described above, the reed switch of the present invention has an advantage in contrast to the drawbacks of conventional reed switches. Compared to mechanical switches such as bimetal switches that do not use magnetism, the reed switch of the present invention can cut off the current when one current is close to zero, so it can handle large currents. It can be seen that it is advantageous from the point of view of contact deterioration when separating.

4 to 6 are modified examples, which are basically the same as those in FIG. 3.

The reed switch shown in FIG. 4(a) has an auxiliary magnetic lead 7 supported by the lead 6 via an insulator 10, and the reed switch shown in FIG. 4(b) has an insulator 10 fixed with a glass 11. This is what I did. In the reed switch shown in FIG. 5, the auxiliary magnetic lead 7 is sealed in a glass container, a lead wire is taken out, the lead 6 is fixed to the auxiliary magnetic lead 7, and the main magnetic lead 5 is attached to the tip of the auxiliary magnetic lead inside the glass container. An insulating film 12 is attached to the opposite side. - In the figure, the insulating film 12 is attached to the auxiliary magnetic lead 7 side.

It may also be attached to the main magnetic lead 5 side. A part of the reed switch beam 6 in FIG. 6 is made of a magnetic material, and only a portion 6' near the contact point 9' is made non-magnetic so that it functions as a non-magnetic reed.

The main purpose is to make the magnetic lead 5 and the lead 6 under the same conditions at a location where the container 8 is sealed. For the same purpose, the material near the sealing part of the container 8 of the magnetic lead 5 shown in FIGS. 3 and 4 may be non-magnetic like the lead 6.

When the reed switch of the present invention is connected to an external circuit having an AC power source, an electrostatic attraction force generated by the AC voltage can be generated between the main magnetic lead 5 and the auxiliary magnetic lead 7 when the contacts are opened. The contact closes when the electric attraction force is small, that is, when the voltage is small.

This reduces damage to the contacts during closing. Should the insulating film 1♀ of the reed switch in Figure 5 be made thinner?

Insulating film 12 and insulator 10.1 of the reed switch in FIG.
This can be achieved by using 1 as a dielectric. Of course, the resistance value of the dielectric must be close to that of the insulator. In addition,
It goes without saying that the container used for the reed switch can be similarly used as long as it is made of an insulating material other than glass.

The reed switch 15 of the present invention is used in FIG.

An example of a temperature-sensitive switch in which a temperature-sensitive magnetic body 13 and a permanent magnet 14 are combined is shown. It goes without saying that even if the temperature-sensitive switch is configured with a magnetic circuit other than this, a temperature-sensitive switch with similarly good contact characteristics can be obtained.

As described above, the reed switch of the present invention not only eliminates the drawbacks of conventional reed switches when switching relatively high current loads, but also has improved contact characteristics compared to other non-magnetic switches. It is an excellent reed switch. As a result, we are able to provide an excellent switch that combines the advantages of reed switches, such as good environmental resistance and high reliability, which are inherently good for the industry.

It is a useful invention. Furthermore, a temperature-sensitive switch incorporating the reed switch of the present invention is an application in which the advantages of the reed switch of the present invention are best utilized. This is because temperature changes in temperature-sensitive switches are relatively slow, so changes in the magnetic field applied to reed switches are small, and temperature-sensitive switches that control large loads need to have good contact characteristics. Therefore, a temperature-sensitive switch using the reed switch of the present invention has a large contact capacity, is highly reliable, and also has low noise when opening and closing the contacts.

It is useful as a temperature-sensitive switch for home appliances, automobiles, office machines, etc.

[Brief explanation of drawings]

FIG. 1 is a side sectional view showing a conventional reed switch. Fig. 2 is a circuit diagram showing one state of use of the reed switch, Figs. 3 to 6 are side sectional views showing various embodiments of the reed switch of the present invention, and Figs. 7(a) to (C) are FIG. 3 is a side view of various temperature-sensitive switches using the reed switch of the present invention. DESCRIPTION OF SYMBOLS 1... Conventional reed switch, 2, 2'... Magnetic reed, 3... Glass container, 4... Filled gas, 5
...Main magnetic lead, 6...Lead, 7...Auxiliary magnetic lead, 8...Glass container, 9, 9'...Contact, 10...Insulator, ]1...Glass , 12...
Insulating film, 13', 13'... Temperature-sensitive magnetic material, 14
...Permanent magnet, 15...Reed switch of the present invention,
16... Magnetic gap, 17... Power supply, 18...
load. Kuten Station-59-

Claims (1)

[Claims] 1. A first lead that is sealed in a cantilever spring type inside an insulating container and is made of a magnetic material and has a first contact at its free end and is connected to a first lead wire outside the container. . a second lead in which the vicinity of the free end including the contact point is made of non-magnetic metal and is connected to a second lead wire outside the container;
The free end of the first lead and the second lead are placed in the container.
and a third lead made of a magnetic material disposed in a cantilevered state so as to face each other with a gap on the opposite side from the contact point. and the first lead with the free end of the first lead in contact with the free end of the third lead due to the presence of an external magnetic field.
A reed switch characterized in that an electrical insulator is interposed in the middle of the current path to block the formation of a current path from the lead to the second lead wire through the third lead. 2. In the reed switch according to claim 1,
The third lead is supported on the inner wall of the container at a position different from the first and second leads, so that the electrical insulator is formed as a part of the wall of the container. A reed switch featuring 3. In the reed switch according to claim 1,
A reed switch characterized in that the third lead is cantilevered on the second lead via an electrical insulator. 4. In the reed switch according to claim 1,
The third lead is directly cantilevered on the second lead, and an electrically insulating film is provided on the surface of the free end of the third lead that faces the free end of the first lead. A reed switch characterized by: 5. Claims No. 1. Second. Third. Alternatively, a reed switch for a temperature-sensitive switch, characterized in that the reed switch according to item 4 is used as a reed switch of a temperature-sensitive switch configured by combining a permanent magnet and a temperature-sensitive magnetic material.