JPH0668337B2 - Self-holding gas cutoff valve - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a self-holding type gas cutoff valve which is arranged in a gas device or gas pipe and shuts off a gas passage by an external signal or the like when an abnormality occurs.

2. Description of the Related Art A conventional self-holding type gas cutoff valve is as shown in FIG. 1, in which magnets (permanent magnets) 2a and 2b are attached to the upper part 1 of the coil unit so that the same poles face each other, and the shape becomes a square shape. The coil unit 1 is set on the bent yoke 3. A magnetic piece 4 is crimped on the bottom surface of the yoke 3, and a through hole 5 into which the piece 4 can be fitted has a through hole 5 formed therein.
It is provided in. The coil 6 is wound around the lower part of the coil unit, and both ends 7a and 7b of the winding wire 7 are exposed to the outside. The coil unit 1 is fixed by a base flange 8, and the base flange 8 is crimped to the yoke 3. The bottom end of the plunger 9 and the upper surface of the piece 4 are suction surfaces.
9a is formed, and a Ben rubber rake 10 is caulked at the head end of the plunger 9, and a Ben rubber 11 is attached to the upper part of the Ben rubber rake 10. A spring 12 is provided between the bevel rubber hook 10 and the base flange 8 to form the magnetic circuits 13a and 13b of the magnets 2a and 2b so that the attraction surface 9a of the plunger 9 may be attracted to the piece 4. Adsorption force (the larger the magnetic force of the magnet, the larger the adsorption force) is generated. On the other hand, if a voltage (a pulsed voltage is acceptable) is applied to the winding 7 so that a reverse magnetic field is generated in the direction of canceling out the attraction force, the repulsive force of the spring 12 causes the plunger 9, that is, the rubber bell 11 to pop out, and as shown in FIG. As shown. To cancel this attraction,
The applied voltage when the plunger 9 jumps out is called the operating voltage. Since this spring has a constant spring force,
It is determined by the magnetic force of the magnet that generates the attractive force and the coil resistance that defines the current that flows in the coil that generates the reverse magnetic field. Also, the magnetic force of the magnet becomes stronger as the residual magnetic flux density increases, but this residual magnetic flux density is affected by the ambient temperature, and depending on the type of magnet, the residual magnetic flux density change per 1 ° C temperature: ΔBr / Br / ° C ( The temperature coefficient) is different. Also, the strength of the reverse magnetic field increases as the current flowing through the coil increases, but the coil resistance value is also affected by the ambient temperature. Therefore, when the applied voltage is constant, the magnetic flux density of the reverse magnetic field also depends on the ambient temperature. Receive. Thus, the operating voltage is
It is determined by the magnetic force of the magnet (depending on the magnitude of the residual magnetic flux density) and the resistance value of the coil, and these are related to temperature.

Problems to be Solved by the Invention Conventionally, generally, the same permanent magnets are used (for example, ferrite magnets or rare magnets), and only a magnet having a temperature coefficient of around −0.18% / ° C. is used. If the temperature coefficient of resistance value of the conductor wire is + 0.4% / ℃, the temperature coefficient of magnet is around −0.18% / ℃ due to the influence of coil temperature change on operating voltage. Therefore, the influence of the temperature change of the residual magnetic flux density of the magnet on the operating voltage is larger, and the characteristics are as shown in FIG. In FIG. 4, the solid line shows the operating voltage temperature characteristic of the shut-off valve which operates at the operating voltage standard value _VA at room temperature, and the dotted line shows the operating voltage temperature characteristic in consideration of individual variations. At this temperature, the drive power supply is V
_Since it is _D , it can be used only at a temperature _{equal to} or higher than the operation lower limit temperature T _L in consideration of individual variations.

Also, in a shut-off valve that uses only a magnet with a temperature coefficient of around -0.04% / ° C, the effect of the change in coil resistance on the operating voltage is that the temperature coefficient of the magnet has a temperature coefficient of around -0.04% / ° C. Therefore, the effect on the operating voltage due to the temperature change of the residual magnetic flux density of the magnet is larger, and the characteristics shown in FIG. 5 are obtained. In this case, contrary to what temperature coefficient using only magnet near -0.18% / ° C., high temperature becomes a problem, it will not be used only in operating upper limit temperature T _H or lower. To also enable the T _H higher temperature or T _L lower temperatures, or issues of performance to reduce the variation width than before, so as to reduce the variation width, reduce the inspection pass width in a selection process Then, there was a problem that it had to be selected.

The present invention solves the above-mentioned problems, and provides a shutoff valve which is not affected by the ambient temperature and has stable performance in all temperature ranges as in the prior art.

Means for Solving the Problems In order to solve the above problems, the present invention provides a coil formed by winding a conductor wire around a bobbin having a through hole.
It is placed in the bottom of the inside of the Y-shaped yoke made of magnetic material, and has a valve body at the head end that is made of a magnetic material in the through hole. An elastic body is provided between the valve body and a base flange that fixes the yoke, and the bottom end portion of the plunger is provided on both side portions of the yoke against the biasing force of the elastic body. A pair of permanent magnets that can be attracted via the yoke,
The same poles are provided to face each other, and each magnet of the pair of permanent magnets is configured such that the temperature variation of the residual magnetic flux density is large and the temperature variation of the residual magnetic flux density is small compared to the temperature displacement of the magnetic flux density generated by the coil. The temperature variation of the residual magnetic flux density of the pair of permanent magnets corresponds to the temperature variation of the generated magnetic flux density of the coil.

Action With the above configuration, the temperature variation of the residual magnetic flux density of the permanent magnet differs depending on each permanent magnet, but the temperature variation of the residual magnetic flux density at the plunger abutting portion of the yoke where the magnetic forces of both permanent magnets meet is the same as that of the above two. Since it is an intermediate value and can cope with the temperature variation of the magnetic flux density generated by the coil, the operating voltage that causes the reverse magnetic field required for separating the plunger and the yoke from occurring in the coil is not affected by ambient temperature changes. Instead, it becomes constant and can act over a wide temperature range.

Example One example of the present invention will be described below. This embodiment is the first
The temperature coefficient of the magnet 2a or 2b in the figure is -0.18% / ℃
Use a nearby magnet (for example, a ferrite magnet),
The temperature coefficient of the opposite magnet 2b or 2a is −0.
Except for using a magnet near 04% / ° C (for example, a rare earth magnet), the mechanical structure is the same as that of the conventional shutoff valve, and therefore the description is omitted. However, the temperature coefficient is -0.18%
By combining these two types of magnets by combining a magnet near / ° C and a magnet near -0.04% / ° C, it is possible to reduce the influence of the coil resistance on the operating voltage and the effect of the magnet temperature coefficient on the operating voltage. It is balanced and, as shown in FIG. 3, operates at a substantially constant voltage in all temperature ranges.

EFFECTS OF THE INVENTION As described above, according to the present invention, as the permanent magnets used in the shutoff valve, there are two types of permanent magnets, one having a large temperature displacement of the residual magnetic flux density as compared with the temperature displacement of the magnetic flux density generated by the coil and the other having a small temperature displacement.
By using various types of permanent magnets in combination, the ambient temperature meter can be used at any ambient temperature as long as the operating voltage is equal to or lower than the driving power supply voltage.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram of a shutoff valve according to an embodiment of the present invention and a block diagram of a conventional example and an open state diagram. FIG. 2 is a closed state diagram of the shutoff valve of FIG. FIG. 4 is a diagram showing the operating voltage temperature characteristic of the embodiment of the present invention, and FIGS. 4 and 5 are conventional operating voltage temperature characteristic diagrams. 1 ... Coil unit, 2a, 2b ... Magnet, 3 ...
Yoke, 4 ... piece, 5 ... through hole, 6 ... coil,
8 ... Base flange, 9 ... Blancer, 10 ... Ben rubber bracket, 11 ... Ben rubber, 12 ... Spring, 13a, 13
b ... magnetic circuit

Claims (1)

[Claims] 1. A coil, which is formed by winding a conductor wire around a bobbin having a through hole, is arranged at the bottom of the inside of a yoke made of a letter-shaped magnetic material, and the through hole is made of a magnetic material. And has a valve body at the head end and a bottom end which is provided with a plunger capable of coming into contact with the yoke in a retractable manner, and an elastic body is provided between the base flange for fixedly supporting the yoke and the valve body. , A pair of permanent magnets that can attract the bottom end of the plunger through the yoke against the biasing force of the elastic body are provided on both sides of the yoke with the same poles facing each other. Of the permanent magnets of the pair of permanent magnets, the residual magnetic flux density of which is large and the residual magnetic flux density of which is small as compared with the temperature displacement of the generated pole flux density of the coil. The temperature displacement of the coil corresponds to the temperature displacement of the magnetic flux density generated by the coil. Self-hold gas shutoff valve configured as.