JPH0447615A - Make and break switch - Google Patents

Abstract

PURPOSE:To improve reliability by noncontact switching operation by providing at least one magnetic strain alloy piece, whose one end is fixed and connected to at least one of a pair of contacts, and a magnetic field generating means being arranged around the above and impressing a magnetic field on the magnetic strain alloy pieces while displacing a length of the magnetic strain alloy pieces to switch on/off a pair of contacts. CONSTITUTION:Magnetic strain alloy pieces 11, 12 are oppositely arranged inside an enclosed container consisting of a glass tube 13 or the like, and the respective one side end parts are fixed to the fixed members 14, 15 while the contacts 16, 17 are fixed to the other ends. Then, an exciting coil 22 is arranged round about the outer periphery of a glass tube 13 as a magnetic field impressing means to the magnetic strain alloy pieces 11, 12 to constitute a break switch. In the case of positive magnetic strain of the magnetic strain alloy, when a DC is let flow to the exciting coil 22, the magnetic strain alloy pieces 11, 12 are extended to bring the contacts 16, 17 into mutual contact to get a closed state while when a DC does not flow, the magnetic strain alloy pieces 11, 12 are contracted to get an open state. Further, in the negative magnetic strain of the magnetic strain alloy, when a DC flows, the magnetic alloy pieces 11, 12 get an open state, while getting a closed state, when a DC does not flow.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to a switch for opening and closing electric current, and more particularly to an opening and closing switch using a giant magnetostrictive alloy.

(Prior Art) A reed switch has been known as a switch that opens and closes using a magnetic field.

FIG. 3 is a diagram showing the configuration of an example of a reed switch. In the figure, reference numeral 1.2 denotes a pair of leads made of ferromagnetic material, and these ferromagnetic material leads 1.2 are arranged in a closed container such as a glass tube 3 or the like. In addition, contacts 4.5 are installed on the opposing surfaces of the ferromagnetic leads 1.2, and the contacts are arranged in response to the external magnetic field generated by the excitation coil 6 provided on the outer circumferential side of the glass tube 3. The contact portion 7 according to 4.5 is opened or separated, and the current is connected accordingly. That is, it is a switch in which the electric circuit and the magnetic circuit have the same medium (lead).

For example, when describing a structure in which the contact portion 7 closes and current flows when an external magnetic field is applied, the switch function is as follows. When there is no external magnetic field, the contact portions 7 are in an open state and no current flows. On the other hand, when an external magnetic field is applied, the magnetic field causes the ferromagnetic leads 1.2 to undergo elastic deformation and bend, causing the contact portion 7
is closed and current flows. When the external magnetic field is removed, the bending stress applied to the ferromagnetic leads 1.2 is removed, so the ferromagnetic leads 1.2 return to their original states, the contacts 7 are opened, and the current is cut off.

In such a reed switch, the contact portion 7 is sealed inside the glass tube 3 or the like, and the contact portion 7 can be opened and closed in a non-contact manner by the magnetic field generated by the excitation coil 6 provided on the outer periphery of the glass tube 3. Therefore, if the glass tube 3 is filled with, for example, an inert gas, the contact portion 7 can be kept clean at all times, which is advantageous in terms of reliability. It is usually used for applications ranging from 0.5A to I8.

(Problem to be solved by the invention) In recent years, the demand for miniaturization of electrical and electronic components has become even stronger, and there is also a demand for smaller and more reliable reed switches such as those mentioned above. It is rare.

However, when considering miniaturization of the reed switch as described above, the reed pieces themselves cannot be made very thick, so the bending stress of the reed pieces cannot be made very large. Therefore, if the contact part is closed by an external magnetic field and the contact part is welded by Joule heat etc. when current is flowing, the reed piece will return to its original state (the contact part will remain in its original state when the external magnetic field is removed). (separated state)
Since the force that tries to return to the contact point is weak, there is a problem of lack of reliability, such as the possibility that the welded part cannot be separated and the contact part opened by simply removing the external magnetic field.

For this reason, there is a strong desire for a switch that can open and close the contacts without contact and that does not reduce reliability even when downsized.

The present invention has been made to address such problems, and an object of the present invention is to provide an opening/closing switch that can open/close a contactor without contact and has excellent reliability in opening/closing operation. It is something.

[Structure of the Invention] (Means for Solving the Problem) That is, the open/close switch of the present invention includes a pair of contacts, and at least one magnetostrictive alloy having one end fixed and joined to at least one of the pair of contacts. piece, and a magnetic field generating means disposed around the magnetostrictive alloy piece and applying a magnetic field to the magnetostrictive alloy piece, and by displacing the length of the magnetostrictive alloy piece by the magnetic field generating means, It is characterized by opening and closing a pair of contacts.

Note that both of the contacts may be driven by magnetostrictive alloys, or one may be fixed. Further, a contactor driven by a magnetostrictive alloy does not necessarily need to be mechanically joined to a magnetostrictive alloy piece, and does not need to be directly joined as long as a driving force can be transmitted.

(Function) In the opening/closing switch of the present invention, the pair of contacts is opened and closed by utilizing displacement in the length direction of the magnetostrictive alloy piece due to application of a magnetic field. This opening/closing operation can be operated without contact using an external magnetic field, and the peeling force generated by the opening operation is extremely large, so even if the contacts are welded together, the opening/closing operation can be performed with high reliability. be able to.

(Example) Hereinafter, an example of the present invention will be described with reference to the drawings.

FIG. 1 is a diagram showing the configuration of a giant magnetostrictive alloy switch according to an embodiment of the present invention.

In the figure, 11 and 12 are magnetostrictive alloy pieces, and these magnetostrictive alloy pieces ]1, ]2 are placed in a closed container made of a glass tube 13, etc.
The magnetostrictive alloy pieces 11 and 12 are arranged to face each other so that the longitudinal direction thereof corresponds to the direction of displacement thereof. These magnetostrictive alloy pieces 1
1.1.2, one end of each is fixed to a fixing member 14.15 installed in the glass tube 13, and a contact 16.17 is bonded and fixed to the other end of each. .

As the magnetostrictive alloy pieces 11, ]2, it is possible to use Ni-based alloys, Fe-AI alloys, ferrite-based materials, etc. that have been conventionally used as magnetostrictive materials, but it is also possible to use materials with high magnetostriction. In particular, it is preferable to use a giant magnetostrictive alloy made of a rare earth metal-transition metal-based Laves type intermetallic compound because it leads to a smaller and more reliable switch. Such a giant magnetostrictive alloy has an atomic ratio of R (Pel-x-y Co, My) (wherein R is at least one element selected from rare earth elements including Y, Mn, Ni, etc.). , Mg, AI, Ga.

Zn, V, Zr, Ilf', Tj,
Nb, Cu, Ag, Sn, MOL S
At least one element selected from t and I3 is not shown, and X%y%Z is a number that satisfies the following formula.

0≦X≦0.95.0≦y≦0.6.1.5≦2≦4.
0), specifically, Tb-Dy-Pe alloy, Tb-Dy-Pe-Mn
alloys, etc. It is also possible to use magnetostrictive alloys having negative magnetostriction such as 5IIIFe2 and ErFe2.

The pair of contacts 16.17 are made of magnetostrictive alloy piece 11.1.
They are arranged facing each other with a predetermined interval in the displacement direction of the two. Further, the pair of contacts 16.17 are connected to terminals 20.2 via expandable lead wires 18.19 such as copper wires.
1 is electrically connected to.

Further, both ends of the glass tube 13 in which the above-mentioned components are arranged are sealed with terminals 20 and 21 protruding therein, and an inert gas is sealed inside. Then, magnetostrictive alloy pieces 11 and 12 are placed on the outer periphery of the glass tube] 3.
An excitation coil 22 is wound around the excitation coil 22 as means for applying a magnetic field to the opening/closing switch using a magnetostrictive alloy.

Note that it is also possible to use a permanent magnet or the like as the magnetic field applying means.

The opening/closing operation of the switch configured as described above is as shown below.

The switch configured as described above has a structure in which the magnetostrictive alloy piece [1.12] is magnetized by passing a direct current through the excitation coil 22. When no direct current is flowing through the excitation coil 22, the pair of opposing contacts 16, 17 are in a closed state. Then, when direct current is passed through the excitation coil 22, if the magnetostriction of the magnetostrictive alloy is positive, the magnetostrictive alloy 1'+' 11.1
2 is extended and contacts 16 and 17 come into contact, resulting in an open state.

In addition, when the magnetostriction of the magnetostrictive alloy is negative, the excitation coil 22
When a direct current is flowing through the excitation coil 22, the length of the magnetostrictive alloy pieces 1 and 12 is reduced and the contacts 16 and 17 are in an open state, and when no direct current is flowing through the excitation coil 22, the length of the magnetostrictive alloy pieces 11 The length of .12 returns to its original state, and the contact 16.17
becomes a state of discovery.

Next, with reference to FIGS. 2 and 4, we will explain the peeling force that acts on the welded part when the contacts are welded and try to separate them. Compare and explain.

FIG. 2 is a diagram for explaining the peeling force of the welded portion of the switch using the magnetostrictive alloy of the above embodiment, and FIG. 4 is an explanatory diagram of a conventional reed switch. In these figures, (a) shows the open state, and (b) shows the closed state. Here, a case will be described in which a giant magnetostrictive alloy with positive magnetostriction is used. Therefore, in FIGS. 2 and 4, (a) is the state where no magnetic field is applied, and (b) is the state where no magnetic field is applied.
) is the state in which a magnetic field is applied. In the figure, Ω indicates the length of the magnetostrictive alloy piece and the ferromagnetic lead, b indicates its width, and h indicates its thickness.

In the case of a conventional reed switch (Fig. 4), the peeling force F1 is expressed as 4Ω 3 (1), and in the case of a switch using a giant magnetostrictive alloy (Fig. 2), the peeling force F1 is F2 is expressed as F2==E' y Ω (II). Note that in the formula, E represents Young's modulus.

For example, ρ = Icm, b = 2mm, h
= 1 mm, assuming that E (Young's modulus) is equal, and calculating the ratio of peeling forces, F 2 /F, = 2XI-0'
...(m), and it can be seen that the switch using the magnetostrictive alloy according to the present invention has a significantly larger peeling force than the reed switch. Therefore, when welding is taken into account, it can be said that the switch using the giant magnetostrictive alloy described in item 1 is more reliable.

]0 Also, regarding the withstand voltage in the open state, ρ-1. cm
When the saturation magnetostriction is set to λ5-10-3, the gap is 10 to 10 cm.For example, in N2 gas, if it is 200μ or less, the withstand voltage is sufficiently maintained and the arc at the time of opening is extinguished. A sufficient size can be obtained.

In fact, in Figure 1, ρ-5cm5 b = 5mm
.

Two giant magnetostrictive alloy pieces (composition: Tbo, rDyu, 7re, 9, saturation magnetostriction: about 1O-3) 1] and 12 having dimensions of h=Imm are prepared, and a contact made of Ag is attached to the tip thereof. Attach the contacts 16 and 17 respectively to form an electrical contact, and the distance between the contacts 6 and 17 (2y) is approximately 100 μm.
The giant magnetostrictive alloy pieces 1 are sealed in a glass tube 13 filled with Ar gas with a distance of .
1. Fix the other end of 12 to the glass tube 13, and
A magnetizing winding (excitation coil 22) was provided on the outside of the switch to produce a switch having external dimensions of about 11 cm x I-cmφ.

When a DC magnetic field of 800 AT was applied by an external winding, the contacts 16 and 17 were in an open state, and when the magnetic field was reduced to zero while a current of 50 Hz and LA was flowing in this state, The contacts change to an open state,
Current no longer flows. From the above, it was confirmed that the switch using the magnetostrictive alloy of the present invention has a sufficient function as a current switch.

In the above embodiments, the magnetostrictive alloy pieces are bonded and fixed to both sides of the contactor, but depending on the magnitude of the magnetostriction of the magnetostrictive alloy, a structure in which the magnetostrictive alloy piece is bonded to only one of the contactors may also be used. , it is possible to obtain the effects of the present invention.

[Effects of the Invention] As explained above, in the open/close switch according to the present invention, when the contacts are welded, the peeling force required by the opening operation is extremely large. It is possible to provide a switch with high compatibility.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing the configuration of an on-off switch according to an embodiment of the present invention, and FIGS. 2 (a) and (b) are diagrams for explaining the opening force acting on the contact of the on-off switch of the present invention. , Fig. 3 is a sectional view showing the configuration of a conventional reed switch, and Fig. 4 (
Figures a) and (b) are diagrams for explaining the separation force acting on the contacts of a conventional reed switch. 11, ]2... Magnetostrictive alloy piece 13...
Glass shield, ]4.1-5...Fixing member, 16.
17... Contact, ]8, ]9... Lead wire, 20.21... Terminal, 22...
excitation coil. Applicant: Toshiba Corporation

Claims (1)

[Scope of Claims] A pair of contacts; at least one magnetostrictive alloy piece having one end fixed and joined to at least one of the pair of contacts; and a magnetostrictive alloy piece disposed around the magnetostrictive alloy piece, the magnetostrictive alloy piece having one end fixed and joined to at least one of the pair of contacts. An opening/closing switch comprising: a magnetic field generating means for applying a magnetic field to an alloy piece, and opening and closing the pair of contacts by displacing the length of the magnetostrictive alloy piece by the magnetic field generating means.