JPH0532921Y2 - - Google Patents

Description

[Detailed description of the invention] [Field of industrial application] The present invention relates to a reed relay. More specifically, the present invention relates to a reduction in voltage between contacts (thermal electromotive force) generated between contacts of a reed relay.

[Conventional technology]

FIG. 2 shows a conventional general type reed relay, and FIG. 3 shows a conventional low thermal electromotive force type reed relay.

In FIG. 2, reference numeral 1 denotes an excitation coil which is wound around the switch section A. The switch leads 3 and 4 are magnetized by the electromagnetic force generated by passing a current through the excitation coil 1, and the switch is brought into contact or opened within the glass tube 2.

As described above, the switch leads 3 and 4 are made of a ferromagnetic material (for example, nickel-based metal) so as to be driven by the electromagnetic force from the coil 1, and one of the switch leads 3 and 4 is made of a ferromagnetic material (for example, a nickel-based metal) so as to be able to open and close the contacts. The switch lead 4 is provided with a movable part. That is, a switch element is formed within the glass tube 2. For example, when mercury is sealed in the glass tube 2, the liquid mercury is present between the contacts, which reduces the contact resistance between the switch contacts, increases the current flowing through the switch element, and prevents chattering. effect can be obtained.

5 and 6 are wiring leads, which are made of copper or the like, for example. The wiring leads 5 and 6 are connected to the switch leads 3 and 4 at points a and b. The reed relay shown in FIG. 2 is connected to an external electric circuit via the wiring leads 5 and 6.

The reed relay shown in Fig. 2 generates heat because current flows through the excitation coil 1, and this heat is transferred to the switch lead 3,
4 is also transmitted. The heat from the switch leads 3 and 4 is transferred to the wiring leads 5 and 6 and escapes.
Generally, heat escapes from the right lead (switch lead 3).
+ wiring lead 5) and the left side lead (switch lead 4 + wiring lead 6) are unbalanced. In a relay in which mercury is sealed in the glass tube 2, there is a mercury reservoir on one side, so the heat capacity is greatly different between the right lead and the left lead, which further increases the imbalance in heat escape. Of course, even with dry reed relays that do not contain mercury, there is generally an imbalance in heat dissipation. Therefore a
There is a temperature difference between point and point b.

In the configuration shown in FIG. 2, dissimilar metals, ie, nickel-based metals (switch lead 3,
4) and copper metal (wiring leads 5, 6), and as mentioned above, there is a temperature difference between points a and b, so based on this temperature difference, the voltage (heat (due to electromotive force) is generated. The voltage difference due to this thermoelectromotive force is 1 when the temperature difference between point a and point b is 1.
It becomes about 40 μv at ℃. This value is too large to be ignored by precision measuring instruments.

The configuration shown in FIG. 3 has been devised in the past to reduce the voltage between the contacts due to such thermoelectromotive force. The reed relay shown in Figure 3 is made of ceramic
A new chip 9 is provided, and the ceramic chip 9 is configured to eliminate the temperature difference between two points (point c and point d) where dissimilar metals are connected. Components with the same component numbers as in Figure 2 are shown in Figure 2.
It is the same as the one shown in the figure.

In Figure 3, ceramic chips 9 and 2 are shown.
The two switch reaches 3 and 4 are connected by connection leads 7 and 8, respectively. This connection lead 7, 8
Since the switch leads 3 and 4 are made of the same metal material, that is, nickel-based metal, no thermoelectromotive force is generated at points a and b.

The front and back surfaces of the ceramic chip 9 are provided with a metal material in advance by vapor deposition, etc., and the connection lead 7 and the wiring lead 5 are attached to this part by soldering or the like, and the connection lead 8 and the wiring lead are attached to the other side. Lead 6 is connected.

Since the ceramic chip 9 has good thermal conductivity, the temperature difference between the connection point d between the connection lead 7 and the wiring lead 5 and the connection point c between the connection lead 8 and the wiring lead 6 can be considered to be zero. In other words, since the temperatures at point c and point d, which are the junction points of dissimilar metals, are the same in Figure 3, the voltage between the switch contacts is almost
It becomes 0v.

[The problem that the idea aims to solve]

The conventional low thermal electromotive force type reed relay shown in Figure 3 has the advantage of reducing the effects of thermal electromotive force, but
Problems include the need for expensive ceramic chips, the complexity of manufacturing, and the difficulty in miniaturizing the ceramic chips because they take up space.

An object of the present invention is to provide a reed relay that does not require a ceramic chip and can reduce the effects of thermoelectromotive force with a simple configuration.

[Means to solve the problem]

In order to solve the above-mentioned problems, the present invention has a switch lead that is made of a ferromagnetic material and has a movable part that can open and close the contacts, and that is driven by electromagnetic force from an excitation coil to open and close the contacts. 3,4
, wiring leads 5 and 6 made of a metal material different from the switch lead, and a pair of thin wire leads 50 and 60 that are thinner than the switch lead and made of the same kind of metal material as the wiring lead,
The switch lead and the wiring lead are connected to each other by these thin wire leads.

[Effect]

In this invention, by reducing the heat dissipation from the switch leads, the two switch leads are made to have the same temperature.
This eliminates the temperature difference between the two connection points (point c and point d) of dissimilar metals, thereby reducing the influence of thermoelectromotive force.

〔Example〕

Hereinafter, the present invention will be explained in detail using the drawings.

FIG. 1 is a diagram showing an embodiment of a reed relay according to the present invention.

The difference between FIG. 1 and FIG. 2 is that thin wire leads 50, 60 are newly provided to connect switch leads 3, 4 and wiring leads 5, 6. That is, the thin wire lead 50 connects the switch lead 3 and the wiring lead 5 (points b and d), and the thin wire lead 60 connects the switch lead 4 and the wiring lead 6.
Connect between (point a and point c). The thin wire leads 50, 60 are made of the same kind of metal material as the wiring leads 5, 6, and thin wires are used for the switch leads 3, 4.

In this way, in the present invention configured to connect the switch leads 3, 4 and the wiring leads 5, 6 with wires thinner than the switch leads 3, 4, the switch leads 3, 4 are connected due to the heat generated by the excitation coil 1. , 4 rises in temperature, the heat is transferred to the thin wire lead 5.
Heat is cut off at 0.60. That is, as the heat of the switch leads 3 and 4 is thermally isolated by the thin wire leads 50 and 60, the temperature difference between points a and b becomes small, and the thermoelectromotive force between points a and b is reduced. Can be made smaller. Connection with an external electric circuit is made via the wiring leads 5 and 6, but since the wiring leads 5 and 6 and the thin wire leads 50 and 60 are made of the same type of metal material, the wiring leads 5 and 6 are made of the same metal material. ,6
No thermal electromotive force is generated at the connection points a and b between the wire and the thin wire leads 50 and 60. Therefore, the thin wire leads 50, 6
In the present invention configured to perform thermal isolation at 0, it is possible to obtain a reed relay with a small thermoelectromotive force as a whole.

In addition, in the example, as the thin wire leads 50 and 60
A 0.1φ copper wire was used. In addition, within the limit that the reed relay of the present invention satisfies the resistance guaranteed as specifications (resistance between the two wiring leads 5 and 6),
If the lengths of the thin wire leads 50 and 60 are made longer, heat radiation can be further improved. By doing this, the amount of heat conducted through the thin wire leads 50, 60 becomes small,
Heat radiation from the switch leads 3 and 4 is hindered. Therefore, every part of the two switch leads 3 and 4 has a uniform temperature. That is, the temperatures at the connection point d between the switch lead 3 (nickel-based material) and the thin wire lead 50 (copper) and the connection point c between the switch lead 4 (nickel-based material) and the thin wire lead 60 (copper) are equal; (or almost the same temperature), these two points c,
The voltages due to the thermoelectromotive force generated at d are equal. Therefore, no voltage is generated between the switch contacts.

[Effects of this invention]

As described above, according to the present invention, the influence of thermoelectromotive force can be reduced with a simple configuration that requires only the attachment of thin wire leads (no need for ceramic chips). Therefore, a very inexpensive and compact reed relay can be manufactured. According to actual measurements, the conventional (second
Figure) In reed relays, a voltage of 30 to 50 μV was generated between the contacts, but according to this application, it can be reduced to a few μV.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing an embodiment of a reed relay according to the present invention, and FIGS. 2 and 3 are diagrams showing a conventional example. 1... Excitation coil, 2... Glass tube, 3, 4...
...Switch lead, 5, 6...Wiring lead, 5
0,60...Thin wire lead.

Claims (1)

[Claims for Utility Model Registration] Switch leads 3 and 4, which have a movable part made of ferromagnetic material and can open and close contacts, and which are driven by electromagnetic force from an excitation coil to open and close the contacts. , wiring leads 5 and 6 made of a metal material different from the switch lead, and a pair of fine wire leads 5 that are thinner than the switch lead and made of the same kind of metal material as the wiring lead.
0 and 60, and the reed relay is characterized in that the thin wire leads connect between the switch lead and the wiring lead, respectively.