JPH0253900B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a magnetic proximity switch device that utilizes a self-holding magnetic switch body that self-holds a switch state among magnetic switches that change the switch state by the action of magnetic force, and further relates to Specifically, the present invention provides a magnetic proximity switch device with a simple structure that switches the switch state by the approach of a magnetically permeable body and functions to self-maintain the switched state even if the magnetically permeable body separates. The purpose is to

Many magnetic proximity switches that utilize reed switches or magneto-electric transducers are manufactured and used for various functions, but conventionally, the switch state is changed by the approach of a magnetically permeable body, and when the magnetically permeable body separates. However, if an attempt was made to obtain a magnetic proximity switch device that functions to self-maintain the switched state, it would be extremely complicated and expensive.

For example, a magnetic proximity switch device that performs the above functions may include a magnetic switch body for ON signals and a magnetic switch body for OFF signals, and these magnetic switch bodies are connected to a flip-flop circuit. However, such a device not only requires two expensive magnetic switch bodies, but also requires a flip-flop circuit, and is prone to malfunctions due to the magnetic force acting on each magnetic switch body acting on the other magnetic switch body. In order to prevent
It is necessary to completely magnetically shield the space between both magnetic switch bodies to prevent mutual magnetic interference, and for this reason, it is necessary to provide a magnetic shielding iron plate, etc., making the overall structure of the device complicated. At the same time, it has become expensive, and furthermore, it has become impossible to achieve sufficient miniaturization.

The present invention was devised to eliminate the drawbacks and dissatisfied points of the conventional example described above, and includes a self-holding magnetic switch and two permanent magnets that apply constant magnetic force in opposite directions to the magnetic switch. The magnetic force of either of the two permanent magnets is blocked from acting on the switch body by a magnetically permeable body, thereby causing the switch body to perform a switching operation.

Embodiments of the present invention will be described below with reference to the drawings.

The magnetic proximity switch device 1 according to the present invention includes one self-holding magnetic switch body 2 and a first gap 5 on one side of the switch body 2 through which a first drive plate 7 made of a magnetically permeable material enters and exits. The first permanent magnet 3 is located facing each other with one magnetic pole (for example, N pole), and the second drive plate 8 made of a magnetically permeable material moves in and out of the other side of the switch body 2. A second permanent magnet 4 is located opposite to the first permanent magnet 3 with the same magnetic pole (for example, N pole) with a gap 6 therebetween.
The permanent magnets 3 and 4 are provided with a magnetic force sufficient to cause the switch body 2 to perform a switching operation.

The self-holding magnetic switch body 2 is not limited in its structure and constituent members, and when a magnetic force of a certain value or more and in a certain direction acts, the self-holding magnetic switch body 2 switches its switch state and the magnetic force stops acting. However, when the above-mentioned switched state is self-maintained, and when a magnetic force below a certain value and in a certain direction is applied, it switches to the opposite switch state, and even if this magnetic force disappears, this switch state remains the same. It functions to self-maintain the switched state of the switch.

An example of this switch body 2 is one having a structure as shown in FIG.

In this FIG. 3, 9 is a magnetoelectric conversion element such as a Hall element, and this magnetoelectric conversion element 9 includes, for example,
A 10V DC power supply 10 is connected in series, so this magnetoelectric conversion element 9 is connected between terminals A and B.
An output corresponding to the direction of the magnetic flux acting on the magnetic flux and the magnetic flux density B[G] is extracted.

The output of this magnetoelectric conversion element 9 is inputted to one input terminal of an operational amplifier 12 via a resistor, and the other input terminal of this operational amplifier 12 is connected to a DC power supply 11 via a resistor.

In the switch body 2 of FIG. 3, the voltage value of the DC power supply 11 and the operation amplifier 12 are
By appropriately setting the values of the resistor connected to the other input terminal of the switch and the feedback resistor, it is possible to provide the operational amplifier 12 with a dead band of a certain width, thereby giving the switch body 2 hysteresis characteristics. It can be done.

Further, the switch body 2 shown in FIG.
Bias magnet 13 that always applies a constant magnetic force to
It has a configuration in which it is assembled with.

The switch body 2 shown in FIGS. 3 and 4
Although the above examples are all constructed using a non-contact type magnetoelectric transducer 9, it is also possible to achieve this using a contact type switch body such as a reed switch. Needless to say.

In this way, the switch body 2 is a self-holding type. To briefly explain the self-holding function of the switch body 2, as shown in Fig. 2, the switch body 2 is operated by a magnetic flux having a magnetic flux density of B _ON or higher. The switch state is switched to the on state by
When the acting magnetic flux density becomes less than the magnetic flux density B _OFF ,
It has a hysteresis switch characteristic that switches the switch state to the OFF state, and the magnetic flux density
It is placed in a magnetic field with a magnetic flux density B _O that is smaller than B _ON but larger than the magnetic flux density B _OFF , so that, for example, a magnetic flux with a magnetic flux density greater than or equal to the magnetic flux density B _ON acts on it and switches it to the on state. After that, even if the effect of this magnetic flux disappears, the magnetic flux density B _O which is higher than the magnetic flux density B _OFF is still acting, so the switch will remain in the on state, self-maintaining the switch state, and conversely, the switch will remain in the on state. Even when the magnetic flux density becomes less than the magnetic flux density B _OFF , the self-holding function of the switch state is exerted in the same way.

Switch body 2 with such a self-holding function
On the other hand, the first permanent magnet 3 is set to have a magnetic force that can cause a magnetic flux with a magnetic flux density B1 larger than the magnetic flux density B _ON to act on the switch body 2,
Further, the second permanent magnet 4 reduces the magnetic flux density acting on the switch body 2 to a magnetic flux density B2 which is lower than the magnetic flux density B _OFF .
Furthermore, the magnetic forces of both permanent magnets 3 and 4 act in opposite directions.

Note that it is convenient to set the absolute values of the magnetic forces of both permanent magnets 3 and 4 to be equal, and to set the relationship B1+B2= _BO .

In the illustrated embodiment, two permanent magnets with exactly the same magnetic force are arranged so that the same magnetic poles are directed toward the switch body 2 and are oriented in opposite directions. When the drive plates 7 and 8 are not in the inserted position, the magnetic flux density of the magnetic force acting on the switch body 2 is set to be the magnetic flux density B _O.

Since the switch device 1 according to the present invention has the above-described structure, the switch switching operation is performed as follows.

That is, assuming that the switch body 2 is now in the OFF state, when the second drive plate 8 moves forward (raises in FIG. 1) from this state and enters the second gap 6, this second Because the second drive plate 8 has entered the gap 6 between the two, the action of the magnetic flux from the second permanent magnet 4 on the switch body 2 is blocked. As a result, the magnetic flux density acting on the switch body 2 becomes a magnetic flux density B1 which is greater than the magnetic flux density B _ON , so the switch body 2 changes its switch state from the OFF state to the ON state. Switch to state.

From this state, the second drive plate 8 moves to the second gap 6.
Even if the magnetic flux of the second permanent magnet 4 comes to act on the switch body 2 by separating from the inside, the magnetic flux of the second permanent magnet 4 only cancels out the magnetic flux of the first permanent magnet 3. Therefore, the magnetic flux density acting on the switch body 2 is the magnetic flux density B _O
Therefore, the switch state is self-maintained, that is, the switch state is self-maintained in the on state.

On the contrary, when the first drive plate 7 enters the first gap 5, the switch state of the switch body 2 becomes the OFF state, and the first drive plate 7 enters the first gap 5.
Even if the drive plate 7 is detached, this switch state, ie, the off state, is maintained by itself.

As described above, the switch device according to the present invention is composed of one self-holding magnetic switch body 2 and two permanent magnets 3 and 4, and does not require any additional circuitry as other components. Since the number of component parts is extremely small, it can be manufactured at low cost, and the structure is extremely simple, so it can be manufactured easily.

In addition, two permanent magnets 3 and 4 are placed with one switch body 2 in between, with a gap 5 between them and the switch body 2.
6 is simply opened and arranged, the whole can be manufactured extremely compactly.

Furthermore, as described above, it has an extremely simple structure and can be manufactured in a sufficiently small size, making it easy to handle, maintain, and manage.

As is clear from the above description, the magnetic proximity switch device according to the present invention has an extremely simple configuration, so it can be manufactured extremely inexpensively and easily, and it can be manufactured sufficiently small. It is easy to handle, maintain, and manage, and since the magnetic force from one permanent magnet is switched using the magnetic shielding function of the drive plate, stable switch operation can always be obtained. It exhibits excellent effects.

[Brief explanation of drawings]

FIG. 1 is a layout diagram showing the basic configuration of the device of the present invention. FIG. 2 is an operation diagram for explaining the operation of the switch body. Figures 3 and 4
The figures are configuration diagrams showing different embodiments of the switch body. Explanation of symbols, 1; Switch device, 2; Switch body, 3, 4; Permanent magnet, 5, 6; Gap, 7, 8;
Drive plate, 9; magnetoelectric conversion element, 13; bias magnet.

Claims (1)

[Claims] 1. A self-holding magnetic switch body, and a first gap located on one side of the self-holding magnetic switch body, through which a drive plate made of a magnetically permeable material enters and exits, and facing the first magnetic switch body with one magnetic pole. a second permanent magnet located opposite to the first permanent magnet with the same magnetic pole, with a second gap formed on the other side of the switch body through which a drive plate made of a magnetically permeable material enters and exits; A magnetic proximity switch device comprising: applying magnetic force to both permanent magnets to cause the switch body to perform a switching operation.