JP2998432B2 - Shut-off valve - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a shutoff valve used as a shutoff actuator of a gas shutoff device for preventing a gas accident from occurring.

[0002]

2. Description of the Related Art Conventionally, various safety devices have been used in order to prevent a gas accident having a high risk of causing a catastrophe once it occurs. 2. Description of the Related Art In recent years, a gas shutoff device that detects abnormal use of gas, gas leakage, and the like and shuts off gas has attracted attention. In particular, in recent years, due to the ease of gas piping and the advantages of low cost, etc., the flow rate of the gas is monitored by a flow sensor built into the gas meter, and the usage status of the gas is judged by a microcomputer (microcomputer). If the danger of the gas is predicted, the effectiveness of the gas meter with a built-in microcomputer type gas shut-off device using a battery power supply that shuts off the gas with the gas shut-off valve built into the gas meter was evaluated, and guidance from the government was given as the core of the gas safety device. Originally, it has been promoted nationwide as a "microcomputer meter." As a shut-off valve of a microcomputer type gas shut-off device, gas is shut off by applying a current only at the moment of operation to suppress battery consumption, and using a self-holding electromagnetic solenoid that holds the state by a permanent magnet or a spring in other cases as an actuator. Valves are mainly used.

An example of the above-described conventional gas shut-off valve will be described below with reference to the drawings.

The conventional shut-off valve shown in FIG. 5 is configured as follows. The valve body 69 includes a valve rubber 75 provided so as to be able to contact the valve seat 70 provided in the valve chamber 82 and a valve rubber 7.
5 is disposed between the valve seat 70 and the valve seat 70 so as to be able to be sandwiched between the valve rubber 75 and the valve rubber 75. And a plunger 63 made of a magnetic material and fixed to the plunger 63.
The spring 68 is compressed and arranged between the valve rubber receiver 76 and the flange 71 fixed to the valve chamber 82 so as to urge the valve body 69 in the direction of pressing against the valve seat 70.
A first yoke 6 having a center hole in which the plunger 63 is loosely inserted coaxially with the plunger 63 on the opposite side of the valve body 69 across a flange 71 having a hole through which the plunger 63 can penetrate.
4, and a core 62 made of a magnetic material is disposed coaxially so that one end thereof can contact the other end of the plunger 63. The core 62 has one end of the permanent magnet 61 in contact with the other end.
A pipe 72 is inserted into the center hole of the first yoke 64 and the hole of the flange 71, the plunger 63 is slidably inserted into one end of the inner hole on the flange 71 side, and the core 62 is inserted into the other end inside. It is. The pipe 72 has an electromagnetic coil 67 around which the plunger 63 can be excited by applying a current. The second yoke 65 is attached to the other pole of the permanent magnet 61, is formed in a U-shape outside the electromagnetic coil 67, and has an end coupled to the first yoke 64. The first packing 73 seals between the flange 71 and the pipe 72, and the second packing 74 seals between the pipe 72 and the core 62.

[0005] Regarding the shut-off valve configured as described above,
The operation will be described below. In a valve-opening holding state in which the valve body 69 holds a state where there is a gap between the valve body 69 and one end of the core 62, one end of the plunger 63 abuts. Therefore, the magnetomotive force of the permanent magnet 61 is reduced by the core 62, the plunger 63, the first yoke 64, and the second yoke 6.
5 and a permanent magnet 61 are formed to generate a suction force 85 for attracting the plunger 63 to the core 62 on the attraction surface 83, and the plunger 63 is applied to the core 62 against a reaction force 86 of the spring 68. Holds by suction.

Next, the moment of the valve closing operation will be described. When a current is applied to the electromagnetic coil 67 in a direction that generates a magnetomotive force in the direction opposite to the magnetomotive force generated by the permanent magnet 61, the magnetic flux generated by the electromagnetic coil 67 causes the magnetic flux generated by the electromagnetic coil 67 to travel in the same path as the magnetic circuit 84 in the second magnetic field. A circuit 87 is formed. Here, the magnetic flux passing through the attracting surface 83 is shown by the addition of the magnetic flux flowing through the second magnetic circuit 87 in the same path and opposite to the magnetic circuit 84. As a result, the magnetic circuit 84 is demagnetized and the attractive force 85 decreases. Eventually, the force becomes smaller than the reaction force 86 of the spring 68 and the balance of the force holding and holding the plunger 63 to the core 62 on the suction surface 83 is lost, and the plunger 63 moves by being urged by the reaction force 86 to move, and the valve body 69 moves. Comes into contact with the valve seat 70 to seal the gas and the valve is closed. In the valve-closed holding state, the plunger 63 is separated from the core 62 and the magnetic resistance at the attraction surface 83 is increased, so that the magnetic flux generated in the magnetic circuit 84 is small and the attraction force 85 is smaller than the reaction force 86. Therefore, the valve body 69 is provided with the reaction force 8 of the spring 68.
6 and is kept in the closed state pressed against the valve seat 70.

FIG. 6 is a sectional view showing another example of the conventional shut-off valve. The gas shut-off valve of FIG. 6 is substantially the same as the conventional example shown in FIG.
Is added. The end of the pipe 72 containing the core 62 is inserted into the center hole of the third yoke 66 having a tubular shape.
The end is locked to the expanded portion at the end of the pipe 72 so that the end is kept out of contact with the second yoke 65.

The operation of the gas shut-off valve constructed as described above is substantially the same as that of the gas shut-off valve shown in FIG. 5, so that the function of the third yoke 66 will be mainly described. The magnetic resistance, which is one of the factors to be determined, will be described. The magnetic resistance in the magnetic circuit increases in proportion to the magnetic gap, that is, the distance of the nonmagnetic material through which the magnetic flux passes.
In addition, when a current is applied to the electromagnetic coil 67 in a direction that generates a magnetic flux in a direction opposite to the magnetic flux of the magnetic circuit 84 by the permanent magnet 61 in FIG. 5, the generated magnetic flux passes through the same path as the magnetic circuit 84 as described above. And the second magnetic circuit 87 in the opposite direction
At this time, the permanent magnet 61 acts as a magnetic gap similarly to the nonmagnetic material, and is regarded as a magnetic resistance that obstructs the flow of the magnetic flux generated by the electromagnetic coil 67.

In the shut-off valve shown in FIG. 6, the magnetomotive force of the permanent magnet 61 forms a magnetic circuit 84 similarly to the shut-off valve shown in FIG.
By providing the third yoke 66, a second magnetic circuit 87 connecting the core 62, the third yoke 66, the second yoke 65, and the permanent magnet 61 is formed.

Next, a case where a current is applied to the electromagnetic coil 67 in a direction that generates a magnetomotive force in a direction opposite to that of the permanent magnet 61 will be described. In this case, the permanent magnet 61 acts as a magnetic gap with respect to the magnetic flux generated by the electromagnetic coil 67 as described above, and is regarded as a magnetic resistance that obstructs the flow of the magnetic flux. 6
The magnetic gap between the second yoke 65 and the second yoke 65 is small. Specifically, the sum of the gap distances between the core 62 and the third yoke 66 and between the third yoke 66 and the second yoke 65 is smaller than the thickness of the permanent magnet 61. Therefore, the magnetic resistance of the path from the core 62 to the second yoke 65 via the third yoke 66 is smaller than that of the path from the core 62 to the second yoke 65 through the permanent magnet 61. As a result, the magnetic flux generated by applying a current to the electromagnetic coil 67 is different from the magnetic circuit 84 of the shutoff valve shown in FIG. 5 in that the magnetic bypass path from the core 62 to the second yoke 65 via the third yoke 66 is provided. Flows in the direction opposite to the magnetic circuit 84 formed by the magnetomotive force of the permanent magnet 61.
8 is formed. In addition, a magnetic bypass path is formed by the provision of the third yoke 66 by the provision of the third yoke 66, so that the third magnetic circuit 8
Since the magnetic resistance of the whole 8 decreases, the magnetic flux amount increases from the magnetic flux flowing through the magnetic circuit 84 of the shut-off valve in FIG.

For the above reasons, the shut-off valve of FIG. 6 in which the third yoke 66 is installed is different from the shut-off valve of FIG. 5 in that the magnetic flux of the magnetic circuit 84 formed by the magnetomotive force of the permanent magnet 61, that is, the attracting surface 83 The demagnetizing force for canceling the attraction force 85 that attracts the plunger 63 to the core 62 and attracts and holds the valve body 69 against the reaction force 86 of the spring 68 increases.

Here, the operating characteristics of the shut-off valve shown in FIG. 5 and the shut-off valve shown in FIG. 6 will be described using the relationship between the applied current and the attraction force acting on the valve shown in FIG.

In FIG. 10, the abscissa represents the applied current with the direction in which the magnetomotive force is generated in the direction opposite to that of the permanent magnet 61 being positive, the ordinate represents the attraction force 85 on the attraction surface 83, and Fb represents the shut-off valve of FIG. The suction force characteristic curve, Fc, is the suction force characteristic curve of the shut-off valve in FIG. 6, fbsp, fcsp, and Fb (0), Fc.
(0) and the operating point b and the operating point c are respectively the spring reaction force of the shut-off valve in FIG. 5 and FIG.
And it represents the operating point. Fb and Fc are represented by quadratic functions of the applied current whose coefficients are proportional to the reciprocal of the magnetoresistance. When the applied current for closing the shut-off valve is an operating current i (0), the operating point b and the operating point c are Fb,
It is given at the intersection of Fb and i = i (0).

First, the suction force characteristics of the shut-off valve shown in FIG. 5 will be described. In a state where no current is applied to the electromagnetic coil 67, a suction force Fb (0) acts on the suction surface 83 to provide a spring 68 having a reaction force of fbsp, and the difference ΔFb
The valve body 69 is held by the suction holding force of (0), and the valve opening state is maintained. When an operating current i (0) for closing the shut-off valve is applied to the electromagnetic coil 67, the attractive force at the attracting surface 83 decreases to the operating point b due to the magnetomotive force of the electromagnetic coil 67, and the reaction force fbsp of the spring 68 decreases. Equal, valve element 6
9 cannot be held, and is released by the spring 68 and closed.

Next, the attraction force characteristic of the shut-off valve shown in FIG. 6 will be described. As described above, when no current is applied to the electromagnetic coil 67, the attraction force Fc (0) acts and a spring 68 having a reaction force of fscp. And the difference ΔFc
When the valve body 69 is held by the suction holding force of (0) to maintain the valve open state and the operating current i (0) is applied, the suction force decreases to the operating point c and becomes equal to the reaction force fcsp of the spring 68. As a result, the holding of the valve body 69 becomes impossible, and the valve body 69 is detached and closed by the spring 68.

Here, the suction force characteristics of the shut-off valve of FIG. 5 and the shut-off valve of FIG. 6 will be compared. In the shut-off valve of FIG. 6, when the third yoke 66 is installed, the second magnetic circuit 87 is formed as described above,
Attraction force Fc because the amount of magnetic flux flowing through the magnetic circuit 84 decreases.
(0) is smaller than Fb (0). On the other hand, since the magnetic bypass is formed by the provision of the third yoke 66 and the magnetic resistance of the third magnetic circuit 88 formed by the electromagnetic coil 67 decreases, the slope of the attraction force characteristic curve Fc of the shutoff valve in FIG. It becomes larger than the slope of the suction force characteristic curve Fb of the shutoff valve. The magnitude of the reaction force 86 of the spring 68 becomes fcsp from the operating point c and becomes smaller than fbsp of the shutoff valve in FIG. Then, the suction force Fc (0) and the spring reaction force fcsp
Is greater than the suction holding force ΔFb (0) of the shut-off valve in FIG.

In addition, the gas shut-off valve used as a shut-off actuator of the gas shut-off device is provided with a suction force by a permanent magnet and a reaction force 86 of the spring 68 in order to prevent a valve closing malfunction due to an external impact. It is better that the suction holding force ΔF expressed by the difference That is, it is better that the slope of the attractive force characteristic curve is as large as possible, that is, the magnetic resistance is as small as possible. Considering that the power supply of the gas meter with the built-in microcomputer type gas shut-off device is a battery and has a finite capacity, it is not preferable to increase the operating current for increasing the suction holding force ΔF and lower the operating point.

FIG. 7 is a cross-sectional view of another conventional shut-off valve disclosed in JP-A-63-76794, and FIG. 8 is a cross-sectional view of another conventional shut-off valve disclosed in JP-A-63-186081.
A third yoke 90 is installed between the second magnet 2 and the permanent magnet 61, and FIG.
In the conventional example, the pipe 72, which is usually a non-magnetic material, is formed of a magnetic material to reduce the magnetic resistance of the magnetic bypass path.

The last conventional example is disclosed in Japanese Patent Application Laid-Open No. 63-1258.
No. 77 is introduced. FIG. 9 is a diagram showing a cross section of another embodiment of the conventional shut-off valve in which the third yoke 91 is installed. In the example of FIG. 9, the third yoke 91 has a circular tube shape, an inner peripheral portion is provided on the outer periphery of a pipe 72 in which a core 62 and a permanent magnet 61 are provided, and an end portion is provided with a second yoke 65. It is a structure that is performed. In this configuration, the magnetic gap between the second yoke 65 and the third yoke 91 is reduced to reduce the magnetic resistance of the magnetic bypass path.

[0020]

However, in the above-described conventional configuration, the third yoke is provided, a magnetic bypass path is provided, the magnetic resistance of the entire third magnetic circuit is reduced, and a current is generated by applying a current to the electromagnetic coil. Although the amount of magnetic flux is increased, since a magnetic gap is provided in the magnetic bypass path, a large magnetic resistance exists in the magnetic bypass path itself, and the effect of reducing the magnetic resistance of the third magnetic circuit is insufficient. Is insufficient, the magnetic flux due to the magnetomotive force of the permanent magnet, that is, the demagnetizing force for canceling the attraction force for attracting and holding the valve element is insufficient. There was a problem that the prevention of operation was insufficient.

That is, in the conventional shut-off valve shown in FIG.
A non-magnetic pipe 72 exists between the first yoke 66 and the third yoke 66, and a gap exists between the second yoke 65 and the third yoke 66. Also, in the conventional shut-off valve shown in FIG. 7, the third yoke 90 and the core 62 are in contact with each other, and the magnetic resistance therebetween is extremely small.
There is a gap between the fifth yoke 90 and the third yoke 90, resulting in a large magnetic gap and magnetic resistance.

Similarly, in the conventional shut-off valve shown in FIG. 8, there is a gap between the magnetic pipe 72 forming the magnetic bypass path and the second yoke 65, and in the conventional shut-off valve shown in FIG. The yoke 65 and the third yoke 91 are in contact with each other, but a pipe 72 made of a nonmagnetic material is provided between the third yoke 91 and the core 62.
Exist, and each has a large magnetic resistance.

In addition to the above-mentioned problems, in the structure of the conventional example, the dimensional accuracy of a single component such as the thickness of the permanent magnet 61, the dimensional accuracy of the core 62, the wall thickness eccentricity of the pipe 72, and the assembly dimensional accuracy thereof. , The relative position with respect to the third yoke 66 varies, and the gap of the magnetic gap is not stabilized, so that the magnetic resistance of the magnetic bypass path varies. Therefore, the magnetic resistance of the second magnetic circuit 87 fluctuates, and the amount of magnetic flux due to the magnetomotive force of the permanent magnet 61 flowing through the magnetic circuit 84 fluctuates.
c (0) varies. Further, since the magnetic resistance of the third magnetic circuit 88 varies, the slope of the attraction force characteristic curve Fc of the shut-off valve also fluctuates.
The operating point c at (0) fluctuates and varies. That is, this operation variation is absorbed and the predetermined operation current i
At (0), the load reaction force fcsp of the spring 68 applied for performing the valve closing operation varies. As a result, in manufacturing this shut-off valve, there are problems that various types of springs 68 having different loads fcsp are required to absorb variations in the operation of the shut-off valve, and that a large number of man-hours are required for the adjustment.

In view of the above-mentioned conventional problems, the present invention has a strong impact holding strength due to a strong suction holding force of the valve body, has a small impact resistance, and has a small variation in a magnetic gap, that is, a magnetic resistance. An object of the present invention is to provide a shut-off valve which is less in variability, requires less man-hours for the production adjustment process of the shut-off valve, and can be realized at a low cost with a simple configuration.

[0025]

In order to achieve the above-mentioned object, a first means of the shut-off valve according to the present invention comprises a valve element disposed so as to be in contact with a valve seat, and pressing the valve element against the valve seat. And a first yoke having a hole into which the plunger is loosely inserted, and a first yoke having a hole through which the plunger is loosely inserted, and a plunger disposed substantially coaxially with the plunger. A core for adsorbing the plunger, a permanent magnet joined to the core, an electromagnetic coil capable of loosely inserting the plunger and being excitable, and connecting to the first yoke from the permanent magnet to the plunger through the outside of the electromagnetic coil. A second yoke forming a magnetic circuit; and a third yoke having one end sliding at least against the outer peripheral surface of the core and the other end abutting on the second yoke.

In order to achieve the above object, the second means of the shut-off valve of the present invention, in addition to the first means, has a core and a permanent magnet provided inside the third yoke by being brought into contact with the inner periphery of the third yoke. Things.

In order to achieve the above object, the third means of the shut-off valve of the present invention, in addition to the second means, further comprises a third yoke provided with a core and a permanent magnet having different outer diameters in contact with the inner peripheral portion, And a step is provided in the inner peripheral part to form a different inner diameter,
The axial length of the inner diameter portion on the large diameter side is set long so that a gap is formed between the plane where the core and the permanent magnet abut and the step.

[0028]

According to the first means, one end of the third yoke is slidably joined to the outer peripheral surface of the core and the other end is formed so as to abut the second yoke. Compared to a shut-off valve in which the yoke has a magnetic gap between the second yoke and the core, the magnetic resistance of the magnetic bypass path from the core to the second yoke via the third yoke is extremely small. .

The end of the third yoke provided around the core is slidably inscribed on the outer peripheral surface of the core, and the other end of the third yoke is formed so as to abut the second yoke. Therefore, since there is no magnetic gap between the core and the third yoke and between the third yoke and the second yoke, variations in magnetic resistance are small. The third yoke can be formed from an iron plate or the like subjected to sheet metal processing. Since the third yoke is in direct contact with the second yoke and the core, there is no need for a locking member for maintaining a constant relative position with respect to the second yoke. It can be realized by:

[0030]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a gas shut-off valve according to an embodiment of the present invention will be described with reference to the drawings. FIG. 1 shows the first embodiment of the present invention.
1 is a cross-sectional view of a gas shut-off valve according to an embodiment of the present invention, which is configured as follows. The valve element 9 includes a valve rubber 15 disposed so as to be in contact with the valve seat 10 provided in the valve chamber 22, and a valve disposed so as to be able to hold the valve rubber 15 between the valve seat 10. It is formed of a rubber receiver 16 and a plunger 3 made of a magnetic material, which is fitted into the center hole of the valve rubber 15 in a gas-sealable manner and is fixed to the valve rubber 15 by a valve rubber retainer 17 and a stop ring 18. I have. The spring 8 is compressed and disposed between the valve rubber receiver 16 and the flange 11 fixed to the valve chamber 22 so as to urge the valve body 9 in the direction of pressing against the valve seat 10.
The flange 11 has a hole at substantially the center, through which the plunger 3 can pass. A first yoke 4 having a center hole into which the plunger 3 is loosely inserted coaxially with the plunger 3 on the opposite side of the valve body 9 with the flange 11 interposed therebetween, and one end coaxial with the other end of the plunger 3 so as to be able to abut. Is provided with a core 2 made of a magnetic material.
The core 2 has one end of the permanent magnet 1 attached to the other end. The pipe 12 is inserted into the center hole of the first yoke 4 and the hole of the flange 11. The plunger 3 is slidably inserted into one end of the inner hole on the flange 11 side, and the core 2 is inserted into the other end inside. are doing. The pipe 12 has an electromagnetic coil 7 around which the plunger 3 can be excited by applying a current. The second yoke 5 is attached to the other pole of the permanent magnet 1, is formed in a U-shape outside the electromagnetic coil 7, and has an end coupled to the first yoke 4. The cylindrical third yoke 6 is provided around the inner periphery of the end of the pipe 12 where the core 2 is inserted, and the outer diameter is substantially equal to the inner diameter at the end of the pipe 12. Here, the inner diameter of the third yoke 6 is equal to the outer diameter of the inserted core, the inner peripheral part of the center hole is slidably inscribed with the outer peripheral part of the core 2, and the end part is connected to the second yoke 5. It is shaped to abut. Flange 11 and pipe 1
2 is sealed by a first packing 13, and a space between the pipe 12 and the core 2 is sealed by a second packing 14.

The operation and features of the gas shut-off valve configured as described above will be described below with reference to FIG. In a valve-open state in which the valve body 9 maintains a state in which there is a gap between the valve body 9 and the valve seat 10, one end of the plunger 3 comes into contact with one end of the core 2 so that the magnetomotive force of the permanent magnet 1 is reduced. 2, a plunger 3, a first yoke 4, a second yoke 5, and a magnetic circuit 24 that connects the permanent magnet 1 to the permanent magnet 1. At the attracting surface 23, an attractive force 25 for attracting the plunger 3 to the core 2 is generated. Plunger 3 against reaction force 26
Is adsorbed and held on the core 2. At the same time, by installing the third yoke 6, a second magnetic circuit 27 connecting the core 2, the third yoke 6, the second yoke 5, and the permanent magnet 1 is formed.

Next, a case where a current is applied to the electromagnetic coil 7 in a direction that generates a magnetomotive force in the opposite direction to the magnetomotive force generated by the permanent magnet 1 at the moment of the valve closing operation will be described. In this case, the permanent magnet 1
Acts as a magnetic gap with respect to the magnetic flux generated by the electromagnetic coil 7 as described above, and is regarded as a magnetic resistance that impedes the flow of the magnetic flux. On the other hand, since the third yoke 6 is in direct contact with the core 2 and the second yoke 5 and the reluctance is extremely small, the third yoke 6 passes through the path from the core 2 to the second yoke 5 through the permanent magnet 1 so that the third yoke 6 The path leading to the second yoke 5 via the yoke 6 has a smaller magnetic resistance. As a result, the magnetic flux generated by the electromagnetic coil 7 flows in a magnetic bypass path extending from the core 2 to the second yoke 5 via the third yoke 6, different from the path and direction of the magnetic circuit 24, and the magnetomotive force of the permanent magnet 1 A third magnetic circuit 28 is formed in the opposite direction to the magnetic circuit 24 formed by the third magnetic circuit 24. Therefore, the magnetic flux due to the magnetomotive force of the permanent magnet 1 passing through the attracting surface 23 between the plunger 3 and the core 2 is demagnetized and reduced, and the plunger 3 is attracted and held on the attracting surface 23 against the reaction force 26 of the spring 8. Suction force 25 is reduced, and finally the spring 8
And the balance of the force is lost, the plunger 3 is urged by the reaction force 26 and moves, and the valve 9 moves the valve seat 10.
, The gas is sealed and the valve is closed. Here, paying attention to the amount of magnetic flux flowing through the third magnetic circuit 28, a magnetic bypass path is formed by installing the third yoke 6, but since the third yoke 6 directly contacts the second yoke 5 and the core 2, Since the magnetic resistance between the core 2 and the second yoke 5 becomes extremely small and the magnetic resistance of the entire third magnetic circuit 28 decreases, the amount of magnetic flux flowing through the magnetic circuit 84 of the conventional shut-off valve shown in FIG. .

Therefore, the shut-off valve having a structure in which the third yoke 6 is brought into contact with the second yoke 5 and the core 2 as in the present embodiment is provided by the magnetic flux of the magnetic circuit 24 formed by the magnetomotive force of the permanent magnet 1. That is, the demagnetizing force for canceling the suction force 25 for holding the valve element 9 on the suction surface 23 is increased.

This operating characteristic of the shut-off valve shown in FIG. 1 is represented by using the relationship between the applied current and the attractive force shown in FIG.

In FIG. 10, the horizontal axis represents the applied current with the direction in which the magnetomotive force in the direction opposite to that of the permanent magnet 1 is generated being positive, the vertical axis represents the attraction force 25 of the valve body 9 on the attraction surface 23, and Fa is FIG. Characteristic curve, fasp, and Fa of the shutoff valve of FIG.
(0) and the operating point a represent the spring reaction force of the shut-off valve in FIG. 1, the attraction force by the magnetomotive force of the permanent magnet, and the operating point, respectively. Fa is represented by a quadratic function of the applied current whose coefficient is proportional to the reciprocal of the magnetoresistance. Further, assuming that the applied current for closing the shutoff valve is the operating current i (0), the operating point a is given by the intersection of Fa and i = i (0).

The operating characteristics of the shut-off valve shown in FIG. 1 are represented by a suction force characteristic curve Fa. That is, when no current is applied to the electromagnetic coil 7, the suction force Fa
(0) is provided, and a spring 28 having a reaction force of fasp is provided.
And maintain the valve open state. When an operating current i (0) for closing the shut-off valve is applied to the electromagnetic coil 7,
Due to the demagnetizing force of the electromagnetic coil 7, the attraction force on the attracting surface 23 decreases to the operating point a, becomes equal to the reaction force fasp of the spring 8, and the holding of the valve body 9 becomes impossible, and the valve body 9 is separated and closed by the spring 8.

Here, the suction force characteristics of the shut-off valve of FIG. 1 of the present embodiment and the suction force characteristics of the conventional shut-off valve of FIG. 6 will be compared. In the shut-off valve shown in FIG. 1, the third yoke 6 is formed so as to directly contact the second yoke 5 and the core 2, and the third yoke 6 has a magnetic gap between the second yoke 5 and the core 2. Compared with the shut-off valve of FIG.
The magnetic resistance of the magnetic bypass path from the core 2 to the second yoke 5 via the third yoke 6 becomes extremely small. The magnetic flux generated by the magnetomotive force of the permanent magnet 1 returns from the core 2 to the permanent magnet 1 via the plunger 3, the first yoke 4, and the second yoke 5, and from the core 2 to the third yoke 6, A second magnetic circuit 27 is formed that passes through a magnetic bypass path leading to the permanent magnet 1 via the second yoke 5. Here, the magnetic resistance of the magnetic bypass path is reduced as compared with the shut-off valve of FIG. 6, the amount of magnetic flux flowing to the second magnetic circuit 27 increases, and the amount of magnetic flux flowing to the magnetic circuit 24 decreases. As a result, The suction force Fa (0) is smaller than Fc (0) of the shut-off valve in FIG.

Next, when a current is applied to the electromagnetic coil 7 in a direction that generates a magnetomotive force in the direction opposite to the magnetomotive force generated by the permanent magnet 1, the magnetic flux generated by the electromagnetic coil 7 has the same magnetic resistance as the shut-off valve in FIG. Although the third magnetic circuit 28 is formed through a small magnetic bypass path, since the magnetic resistance of the magnetic bypass path is smaller than that of the shutoff valve in FIG. 6, the attraction force characteristic in which the inclination increases in inverse proportion to the magnetic resistance. The slope of the curve Fa becomes larger than the slope of the suction force characteristic curve Fb of the shutoff valve in FIG. Also, the reaction force 26 of the spring 8 from the operating point a
Is obtained. From these results, it can be seen that the suction holding force ΔFa (0) of the valve element 9 represented by the difference between the suction force Fa (0) and fasp is larger than ΔFc (0). Therefore, the operating current i of the same magnitude as the conventional one
In (0), the magnetic flux due to the magnetomotive force of the permanent magnet 1, that is, the valve body 9
Can be demagnetized more strongly, and as a result, the difference between the attraction force of the permanent magnet 1 and the reaction force of the spring can be set large, and the shock resistance against a valve closing malfunction due to an external impact Is improved. On the other hand, even when a current is applied to the electromagnetic coil in the forward direction with respect to the magnetomotive force generated by the permanent magnet to perform the attraction valve opening operation, a stronger attraction force can be obtained for the same reason.

In the valve-closed holding state, the plunger 3 is separated from the core 2 and the magnetic resistance at the attraction surface 23 is large, so that the magnetic flux passing through the attraction surface 23 is small and the attraction force 25 is smaller than the reaction force 26. Accordingly, the valve element 9 is kept biased by the reaction force 26 of the spring 8 and pressed against the valve seat 10 to maintain the closed state.

The inner periphery of the center hole of the third yoke 6 provided around the core 2 directly inscribes the outer periphery of the core 2, and the end of the third yoke 6 directly contacts the second yoke 5. With such a configuration, variations in magnetic resistance between the core 2 and the third yoke 6 and between the third yoke 6 and the second yoke 5 are small. As a result, the attraction characteristics of the shut-off valve, that is, the relationship between the applied current to the electromagnetic coil 7 and the attraction force are stabilized, and the variation in operating characteristics is reduced. Therefore, the man-hour required for the manufacturing adjustment process in manufacturing the shut-off valve is reduced.

In addition, since the third yoke 6 has a structure in contact with the core 2 and the second yoke 5, the permanent magnet 1 forms the second magnetic circuit 27. The flowing magnetic flux acts as a self-attracting force 29 for attracting the third yoke 6 to the second yoke 5. In addition, since the third yoke 6 is fitted around the outer periphery of the core 2 as a shaft, the third yoke 6 can slide when assembled. Even if the thickness of the permanent magnet 1 and the dimensional variation of the third yoke 6 itself occur, the third yoke 6 is securely attached to the second yoke 5 to fill the gap and eliminate the variation of the magnetic gap, thereby reducing the variation of the magnetic gap. The operation is stabilized, and the locking member of the third yoke 6 is not required, so that it can be realized with a simple configuration. The third yoke 6 itself can be formed from a sheet metal processed iron plate or the like, and mass production can be easily performed.

As described above, the gas shut-off valve of the present invention is formed so that the inner peripheral portion of the center hole of the third yoke 6 is inscribed in the outer peripheral portion of the core 2 and the end portion is in contact with the second yoke 5. As a result, the suction holding force is high, the impact resistance is high, the variation in the operating characteristics of the shut-off valve is small, the number of steps required for the manufacturing adjustment process is small, and the configuration can be realized with a simple configuration.

FIG. 2 is a sectional view of a shut-off valve according to a second embodiment of the present invention. The configuration of the shut-off valve in FIG. 2 is basically the same as the configuration of the shut-off valve in FIG. 1, and the same parts are denoted by the same reference numerals as in FIG. 30 installation structures are different. Although the third yoke 6 in the shut-off valve of FIG. 1 is formed in a circular pipe shape, the inner peripheral portion of the center hole is inscribed in the outer peripheral portion of the core 2 and the end portion is in contact with the second yoke 5. The third yoke 30 of the shut-off valve shown in FIG. 2 is characterized in that, in addition to the above features, the inner peripheral portion of the center hole is also inscribed with the outer peripheral portion of the permanent magnet 1.

The operation of the gas shut-off valve of FIG. 2 configured as described above is the same as that of the gas shut-off valve of FIG.

The effect of the third yoke 30 of the shut-off valve in FIG.
Since the inner peripheral portion of the center hole is in contact with the outer peripheral portion of the permanent magnet 1 as well as the core 2, the center of each of the cylindrical core 2, the permanent magnet 1, and the cylindrical third yoke 30 is formed. The coaxiality of the shaft is improved, and the relative positional relationship between the components is stabilized. Therefore, the core 2, the permanent magnet 1, and the third yoke 30
The surrounding magnetic gap, that is, the magnetic resistance is stabilized, the variation in the magnetic circuit formed therein and the amount of magnetic flux passing therethrough are reduced, and as a result, the variation in the operating characteristics of the shut-off valve is reduced and stabilized. The center hole of the third yoke 30 is the core 2,
Since the permanent magnet 1 is positioned, assemblability is also improved.

FIG. 3 is a sectional view of a shut-off valve according to a third embodiment of the present invention. The configuration of the shut-off valve in FIG. 3 is basically the same as the configuration of the shut-off valve in FIG. 2, and the same parts are denoted by the same reference numerals and detailed description is omitted. , The configuration and the installation structure of the third yoke 33 are different. 3, the core 31 and the permanent magnet 32 have a disk shape, but the outer diameter of the permanent magnet 32 is larger than the outer diameter of the mounting surface of the core 31 with the permanent magnet 32. The third yoke 33 is formed in the shape of a circular tube as in the above-mentioned embodiment, but the inner peripheral portion has a small outer diameter.
And the permanent magnet 32 having a large outer diameter and the two members having different diameters are inscribed. Therefore, a step 33a is provided in the inner peripheral portion of the center hole to form two different inner diameters. The axial length of the inner diameter portion inscribed in the outer peripheral portion of the permanent magnet 32 and the core 3 after assembly is set to be long beforehand.
A cavity 34 having a space represented by d in FIG. 3 is formed between the mounting plane 1 and the stepped surface of the third yoke 33.

Because of the above-described structure, the depth of the concave portion of the second yoke 5 in which the permanent magnet 32 is fitted, the thickness of the permanent magnet 32, and the dimensional variation of the third yoke 33 itself. Occurs, the third yoke 33 can be slid around the outer periphery of the core 31 during assembly, and the axial length of the third yoke 33 is increased by a large-diameter inner diameter portion set in advance. Is formed, the variation is absorbed, and the step portion of the third yoke 33 does not ride on the permanent magnet 32 to form a gap between the second yoke 5 and the second yoke 5. To be laid.

FIG. 4 is a sectional view of a shut-off valve according to a fourth embodiment of the present invention. The configuration of the shut-off valve in FIG. 4 is basically the same as the configuration of the shut-off valve in FIG. 3, and the same parts are denoted by the same reference numerals and detailed description is omitted.
In contrast to the embodiment, the outer diameter of the mounting surface of the core 35 with the permanent magnet 36 is larger than the outer diameter of the permanent magnet 36.
Accordingly, the inner peripheral portion of the third yoke 37 is provided with a step at the inner peripheral portion of the center hole similarly to the third yoke 33 of the embodiment of FIG.
Two different inner diameters are formed, and the axial length of the larger diameter side, that is, the inner diameter portion inscribed in the outer peripheral portion of the core 35, is set to be long in advance, and the assembling plane of the permanent magnet 36 and the core 35 after assembly. A cavity 38 having an air gap indicated by d in FIG. 4 is formed between the first yoke 37 and the step surface of the third yoke 37, which is the same as that described in the embodiment of FIG. For this reason, the core 35 does not ride on the stepped portion of the third yoke 37 to form a gap between the third yoke 37 and the permanent magnet 36, so that the core 35 is securely attached to the core 35.

As in the third yoke of the shut-off valve in the third embodiment shown in FIG. 3 and the fourth embodiment shown in FIG. The length of the inner diameter portion in the axial direction is set to be long in advance, and a structure is formed in which a cavity having a gap is formed between the mounting surface of the permanent magnet and the core and the step surface of the third yoke after assembly. For example, even with a shutoff valve using a permanent magnet and a core having different outer diameters, the same effects as in the first and second embodiments can be obtained.

The detailed shape of the third yoke, that is, the shape, inner and outer diameters, length, thickness, the area of contact with the second yoke, the permanent magnet and the core, etc. of the circular tube portion are combined with the shape of other shutoff valve components. It is determined by the balance of the shutoff valve magnetic circuit configuration and the operation characteristics, but it goes without saying that the detailed shape does not matter as long as the conditions of the configuration of the present invention are satisfied.

[0051]

As described above, the shut-off valve having the configuration according to the present invention has the following effects.

(1) In the shut-off valve according to the first aspect, one end of the third yoke slides on and contacts the outer peripheral surface of the core, and the other end contacts the second yoke. Compared with a shut-off valve in which the third yoke has a magnetic gap between the second yoke and the core, the magnetic resistance of the magnetic bypass path from the core to the second yoke via the third yoke is extremely low. Since it becomes smaller, the amount of magnetic flux generated by the magnetic coil increases, and the magnetic flux due to the magnetomotive force of the permanent magnet, that is, the demagnetizing force for canceling the attraction force of the valve can be increased. Therefore, the balance between the attraction force and the spring reaction force can be greatly reduced with an operating current of the same size as the conventional one, and the difference between the attraction force by the permanent magnet and the reaction force of the spring, that is, the suction holding force, can be increased. Impact strength can be increased.

(2) In the shut-off valve according to the first aspect, the third yoke directly abuts the core and the second yoke, and a self-sucking force is applied to the second yoke at the time of assembling, whereby the outer peripheral surface of the core is used as a shaft. Since it is slid to absorb the dimensional variation and installed securely against the second yoke, the variation in the magnetic gap, that is, the magnetic resistance can be reduced, and the variation in the attraction force characteristics and operating characteristics of the shut-off valve is reduced. The man-hour required for the production adjustment process of the shut-off valve can be reduced.

(3) The shut-off valve according to claim 2 is inserted into the inner peripheral portion of the third yoke so that not only the core but also the permanent magnet is slid and inscribed. The coaxiality of each central axis is improved, and the relative positional relationship of each component is stabilized. Therefore, the variation in the magnetic resistance around the magnetic bypass path is reduced, the amount of magnetic flux passing therethrough is stabilized, and the variation in the operating characteristics of the shut-off valve is reduced and stabilized. In addition, since the third yoke positions the core and the permanent magnet, assemblability is improved.

(4) In the shut-off valve according to the third aspect, a step is formed in the inner peripheral portion of the third yoke to form different inner diameters, the axial length of the large-diameter inner diameter portion is set to be long in advance, and after assembly, Since a cavity having a cavity is formed between the mounting surface of the permanent magnet and the core and the step of the third yoke, even a shutoff valve using a permanent magnet and a core having different outer diameters. The same effects as those of the shut-off valves according to the first and second aspects can be obtained.

[Brief description of the drawings]

FIG. 1 is a sectional view of a gas shutoff valve according to a first embodiment of the present invention.

FIG. 2 is a sectional view of a gas shutoff valve according to a second embodiment of the present invention.

FIG. 3 is a sectional view of a gas shutoff valve according to a third embodiment of the present invention.

FIG. 4 is a sectional view of a gas shutoff valve according to a fourth embodiment of the present invention.

FIG. 5 is a sectional view of a conventional gas shut-off valve.

FIG. 6 is a sectional view of a conventional gas shut-off valve.

FIG. 7 is a sectional view of another example of the conventional gas shut-off valve.

FIG. 8 is a sectional view of another example of the conventional gas shut-off valve.

FIG. 9 is a sectional view of another example of the conventional gas shut-off valve.

10 is a diagram showing the relationship between the applied current plunger and the attraction force between the cores of the shut-off valve in the first embodiment of the present invention shown in FIG. 1 and the conventional shut-off valves shown in FIGS. 5 and 6;

[Explanation of symbols]

 Reference Signs List 1 permanent magnet 2 core 3 plunger 4 first yoke 5 second yoke 6 third yoke 7 electromagnetic coil 8 spring 9 valve body

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) F16K 31/06 380

Claims (3)

(57) [Claims] A valve body disposed so as to be in contact with the valve seat, a spring for urging the valve body in a direction of pressing the valve body against the valve seat, and a magnetic material having the valve body disposed at one end. Plunger, a first yoke having a hole through which the plunger is loosely inserted, a core disposed substantially on the same axis as the plunger, a core for adsorbing the plunger, a permanent magnet joined to the core, and a plunger. An electromagnetic coil that can be inserted and excited, a second yoke coupled to the first yoke to form a magnetic circuit extending from the permanent magnet to the plunger through the outside of the electromagnetic coil, and one end portion having at least an outer peripheral surface of the core And a third yoke slidably in contact with the second yoke and having the other end in contact with the second yoke. 2. The shut-off valve according to claim 1, wherein the third yoke is provided with a core and a permanent magnet in contact with an inner peripheral portion. 3. The third yoke is provided with a core and a permanent magnet having different outer diameters in contact with an inner peripheral portion, and a step is formed on an inner peripheral portion to form different inner diameters. 3. The shutoff valve according to claim 2, wherein the length in the direction is set long so that a gap is formed between a plane where the core and the permanent magnet abut, and the step.