JPH03250519A - Contactless switch - Google Patents

Abstract

PURPOSE:To enhance the contacting reliability of a contact of a switch and prolong its lifetime by entering a pulse signal which is generated by a magneto- striction pulse generating element when the position of a yoke changes, and emitting a switching signal in conformity to the entered pulse signal. CONSTITUTION:When a push button 8 is pushed to cause one end of an arm 6 to move downward, the both ends of a yoke 7 approach the both poles of a permanent magnet 11. Thereby a closed magnetic circuit is formed from the magnet 11 and yoke 7, and the magnetic flux generated from the magnet 11 does not leak to the outside, but is introduced into the yoke 7. Accordingly the magnetic flux given to a Wiegand element 20 will solely be that from No.2 permanent magnet 12, and the core of the element 20 will be magnetized in the opposite direction. Because the direction of manetization of this core is reversed, positive pulses are generated at the ends of a sensing coil 23 and fed to an output circuit 30. When the pushing of a button is released, the yoke 7 is restituted. Accordingly the direction of magnetization of the element 20 is returned to its original state. Thus negative pulses are generated across the coil 23 and fed to the output circuit 30.

Description

[Detailed description of the invention] Background of the invention Technical field The present invention relates to a non-contact switch.

Prior art and its problems Conventional switches include mechanical switches that switch electrical circuits by bringing metal electrical contacts into or out of contact with each other through mechanical displacement.

However, mechanical switches are prone to deterioration of the contact material and lead to contact failures when foreign substances such as abrasion particles of resin from the case or flux are trapped between the contacts, or in adverse environments such as SO2 or H2S gas atmospheres. Therefore, it is difficult to maintain contact reliability. In addition, it is difficult to extend the life of the contacts due to welding and abrasion of the contacts. Furthermore, there is also the problem that chattering, bounce, etc. can cause malfunctions in electronic circuits.

SUMMARY OF THE INVENTION OBJECTS OF THE INVENTION An object of the present invention is to provide a non-contact switch that solves the above-mentioned problems of contact switches.

Arrangement 1 of the Invention Functions and Effects The non-contact switch according to the present invention includes a magnetostrictive pulse generating element, which is arranged at intervals outside the magnetostrictive pulse generating element so that opposing magnetic poles are opposite to each other, and a first magnetic field generating means that provides a magnetic flux to the generating element; a second magnetic field generating means that provides a magnetic flux smaller than the first magnetic field generating means and in the opposite direction; The yoke 1 forms a magnetic closed circuit with the first magnetic field generating means, and has two positions: a first position where the first magnetic field generating means and the yoke are close to each other, and a second position where they are separated from each other. a support mechanism that supports either the first magnetic field generating means or the yoke and moves the first magnetic field generating means or the yoke from one position to the other by pressing a switch push button, and changes the position of the yoke; The present invention is characterized by comprising a signal output means for inputting a pulse signal generated from the magnetostrictive pulse generating element and outputting a switching signal in accordance with the pulse signal.

According to this invention, the direction of magnetization of the magnetostrictive pulse generating element is determined depending on the position of the yoke. That is, when the yoke is in the second position away from the first magnetic field generating means, it is greatly influenced by the magnetic flux of the first magnetic field generating means, which has a large magnetic force, so that the magnetostrictive pulse generating element is When the yoke is magnetized in the direction of the generated lines of magnetic force and reaches the first position where the yoke and the first magnetic field generating means are close to each other, the lines of magnetic force generated by the first magnetic field generating means pass through the inside of the yoke, so the magnetostrictive pulse generating element It is magnetized in the direction of the lines of magnetic force generated by the magnetic field generating means. Therefore, in response to the depression of the switch push button, the positional relationship between the first magnetic field generating means and the yoke changes, so that the direction of magnetization of the magnetostrictive pulse generating element is reversed and a pulse signal is output. A switching signal is generated from the signal output means in response to this pulse signal.

According to this invention, there is no need for metal contacts and the electric circuit can be switched without contact, so there is no wear and tear on the contacts and the switch has a long life. Furthermore, the reliability of the switch operation is improved because poor conductivity of the contacts caused by foreign matter such as abrasion powder of one member and deterioration of the contact materials are eliminated even under adverse environments such as dust and H2S gas atmospheres. Furthermore, since chattering and bounce do not occur even under minute current loads, reliability of switching control is improved without causing malfunction of electronic circuits. Furthermore, since the signal a means is composed of an electronic circuit, it is possible to convert this electronic circuit into an IC.By preparing electronic circuits with various functions in advance and converting them appropriately, a non-contact switch can be created. function can be easily changed.

It is preferable to include means for storing the pulse signal output of the magnetostrictive pulse generating element. As a result, even if a power outage occurs, the output state before the power outage is stored, so that the state before the power outage can be restored after the power outage is restored. Furthermore, since the number of switching operations can be stored, the life of the switch can be predicted based on this storage, and the switch can be replaced before the reliability of the switch deteriorates.

DESCRIPTION OF THE EMBODIMENTS FIG. 1 is a block diagram showing the electrical configuration of a non-contact switch.

When the push button of the non-contact switch is pressed, its displacement is applied to the pulse generating mechanism IO, which outputs a pulse signal.

By applying this pulse signal to the output circuit 30, a switch output is obtained.

FIG. 2 is a perspective view showing the pulse generation mechanism of the non-contact switch, and in this figure, the case is either shown or omitted. FIG. 3 is a sectional view taken along the line ■-■ in FIG. 2.

Permanent magnets are used in non-contact switches 11.12. A yoke 7 and a Wiegand element 20 are included.

A first permanent magnet 11 and a second permanent magnet 12 are arranged on both sides of the Wiegand element 20 so as to be parallel to the Wiegand element 20 and spaced apart from each other by a certain distance. 11
．． 12 is fixed to the non-magnetic support member 4 at its center. The opposing magnetic poles of the first permanent magnet 11 and the second permanent magnet 12 have opposite polarities. Also, the first permanent magnet 1
1 has a larger magnetic force than that of the second permanent magnet 12.

The yoke 7 is bent so that both ends thereof face both ends of the first permanent magnet 11. Further, the yoke 7 is fixed to one end of the arm 6 at its center. The arm 6 has a bottle 5 attached to a bracket 5 fixed to the support member 4 at the other end so that the arm 6 can move up and down.
Supported by A. A compression spring (path shown) is disposed between the arm 6 and the support member 4, and constantly urges the arm 6 upward. The arm 6 is in contact with the lower surface of the push button 8 protruding from the upper surface of the case 1. push button 8
serves as a stopper, and the upward movement of the arm 6 is restricted. When the push button 8 is pressed, the force is transmitted to the arm 6, and as a result, the above-mentioned one end of the arm 6 descends, and as a result, the yoke 7
also descends.

The Wiegand element 20 is a magnetostrictive pulse generating element that outputs a pulse signal by changing the direction of a magnetic field applied from a permanent magnet or the like. Other specific examples of the magnetostrictive pulse generating element include so-called Wiegand effect devices such as permalloy (50Ni-50Fe), amorphous magnetostrictive wires that produce the large Barkhausen effect or Matteucci effect, and the like.

Around such a Wiegand element 20, a fourth
As shown in the figure, a coil 23 is wound. The coil 23 is an output circuit 30 assembled on a board inside the case 1.
It is connected to the. The output of the a-power circuit 30 is taken out from the terminal 9.

5(A) to 5(C) show the operation of the Wiegand element 20, and FIGS. 6(A) and 6(B) show the state in which the magnetization direction of the Wiegand element 20 is as shown in FIGS. 5(B) and 5(C). The pulses that are generated when the signal is reversed are shown.

The Wiegand element 20 is composed of an inner core portion 21 having a weak coercive force and an outer shell portion 22 having a strong coercive force. As shown in FIG. 5(A), it is assumed that the Wiegand element 20 has both the inner core portion 21 and the outer shell portion 22 magnetized in the same direction.

In FIG. 5(B), the magnetization direction of the inner core portion 21 is reversed by applying a small magnetic field in the opposite direction (magnetic fields externally applied to the Wiegand element 20 are represented by symbols S and N). The outer shell 22 is not inverted due to its strong coercive force. This induces a positive voltage pulse in the detection coil as shown in FIG. 6(A).

In FIG. 5(C), when the direction of the applied magnetic field is reversed, the magnetization direction of the inner core portion 21 returns to its original state. As a result, a negative voltage pulse as shown in FIG. 6(B) is induced in the detection coil.

FIGS. 7A and 7B show how the direction of magnetization of the Wiegand element 20 changes as the distance between the first permanent magnet 11 and the yoke 7 changes. Figure 7 (A),
In (B), the yokes 7 are spaced apart in a direction perpendicular to the plane of the paper, but for convenience, they are shown as being spaced apart in a lateral direction.

When the push button 8 is not pressed, the first permanent magnet 11 and the yoke 7 are separated from each other as shown in FIG. 7(A). At this time, both the magnetic flux of the first permanent magnet 11 and the magnetic flux of the second permanent magnet 12 are applied to the Wiegand element 20. The magnetic pole directions of these permanent magnets 11 and 12 are opposite to each other as described above. Since the first permanent magnet 11 has a larger magnetic force than the second permanent magnet 12, the Wiegand element 20 is given magnetic flux in the same direction as the magnetic flux of the first permanent magnet 11 (Fig. (corresponds to the state shown in (A)).

When the push button 8 is pressed and the one end of the arm 6 moves downward, both ends of the yoke 7 and both poles of the first permanent magnet 11 approach each other as shown in FIG. 7(B). As a result, a magnetic closed circuit is formed by the first permanent magnet 11 and the yoke 7, and the magnetic flux generated from the permanent magnet 11 is guided into the yoke 7 and does not leak outside. Therefore, the magnetic flux given to the Wiegand element 20 is only from the second permanent magnet 12, and the inner core of the Wiegand element 20 is magnetized in the opposite direction (corresponding to the state shown in FIG. 5(B)). Since the direction of magnetization of the inner core of the Wiegand element 20 is reversed, the detection coil 2
A positive pulse as shown in FIG.

When the push button 8 is no longer pressed and is released from external force,
The yoke 7 returns to its original position as shown in FIG. 7(A).

Therefore, the magnetization direction of the Wiegand element 20 returns to its original state (corresponding to the state shown in FIG. 5(C)). As a result, negative pulses as shown in FIG. 6(B) are generated at both ends of the detection coil 23 and applied to the output circuit 30.

A block diagram showing the circuit configuration of the output circuit 30 is shown in FIG.

Positive and negative pulses V (FIG. 9(A)) output from the coil 23 wound around the Wiegand element 20 are given to the positive and negative n pulse separation circuit 31. Among the pulses separated by the positive and negative pulse separation circuit 31, the positive pulse V (
9(B)) is applied to the set terminal of the flip-flop 32. By setting the flip-flop 32, the output of the electronic circuit 30 (output of the flip-flop)
rises from OV to the power supply voltage. Also, a negative pulse (vb
(FIG. 9(C)) is applied to the reset terminal of the flip-flop 32.

When the flip-flop 32 is thereby reset, the output of the electronic circuit 30 falls from the power supply voltage to OV. Therefore, the electronic circuit 30 outputs a pulse signal Vo having a pulse width corresponding to the pressing time of the push button 8 as a switching signal (FIG. 9(D)).

The output circuit 30 also includes a memory 33.

This memory 33 is used as a measure against power outage, and always holds the output state of the flip-flop 32, and when a power outage occurs, the output of the flip-flop 33 is set to the state before the power outage after the power outage is recovered.

Furthermore, the number of times the flip-flop 32 has been set or reset (the number of times a pulse signal has been generated) may be stored in the memory 33. By referring to the data stored in the memory 33, the number of switching operations of the non-contact switch can be known, and the switch can be handled before the reliability of the switching operation deteriorates.

In the above-described embodiment, the magnetic force of the first permanent magnet 11 is greater than the magnetic force of the second permanent magnet 12, and each magnet is arranged at an equal distance from the Wiegand element 20, but this invention does not necessarily apply. There is no need to use magnets with different magnetic forces. For example, if two magnets with the same magnetic force are arranged at different distances to the Wiegand element, the magnitude of the magnetic flux density generated by each permanent magnet will change, so the same effect as in the above embodiment can be obtained.

Further, in the above-mentioned embodiments, the switch is configured so that the permanent magnet is fixed and the yoke is moved, or the yoke may be fixed and the permanent magnet is moved.

[Brief explanation of drawings]

Figure 1 is a block diagram showing the electrical configuration of this invention, Figure 2 is a block diagram showing the electrical configuration of this invention.
The figure is a perspective view showing the pulse generation mechanism of the non-contact switch, and FIG. 3 is a cross-sectional view taken along the line ■-■ in FIG. 2. Figure 4 is a front view showing the Wiegand element, Figure 5 (A)
~(C) explains the operation of the Wiegand element,
FIGS. 6A and 6B are waveform diagrams showing pulses generated when the magnetization direction of the Wiegand element is reversed. FIGS. 7A and 7B are plan views showing the positional relationship between the yoke and the magnet as the push button is pressed down. Figure 8 is a block diagram showing the electrical configuration of the output circuit, Figure 9 is a block diagram showing the electrical configuration of the output circuit.
Figures (A) to (D) are waveform diagrams showing input and output waveforms of the output circuit. 7... York. 11...First permanent magnet. 12...Second permanent magnet. 20... Wiegand element. 30... Output circuit.

Claims (2)

[Claims] (1) Magnetostrictive pulse generating element, a first magnetic field generating means that is arranged at intervals outside the magnetostrictive pulse generating element so that opposing magnetic poles are opposite, and that applies magnetic flux to the magnetostrictive pulse generating element. and a second magnetic field generating means that provides a magnetic flux smaller than the first magnetic field generating means and in the opposite direction, which is close to the first magnetic field generating means and forms a magnetic closed circuit between the first magnetic field generating means and the first magnetic field generating means. a yoke for forming the first magnetic field generating means or a support mechanism that supports either one of the yokes and moves the yoke from one position to the other by pressing a switch push button; and a pulse generated from the magnetostrictive pulse generating element when the position of the yoke changes. A non-contact switch comprising: signal output means for inputting a signal and outputting a switching signal in accordance with the pulse signal. (2) The non-contact switch according to claim 1, further comprising means for storing the output pulse signal of the magnetostrictive pulse generating element.