JPH035733Y2 - - Google Patents

Description

[Detailed explanation of the idea] The present invention relates to improvements in solenoid valves.

Generally speaking, when talking about a solenoid valve, when a current is applied to an excitation coil 1 as shown in Fig. 1, a movable iron piece 2
is drawn upwards, opening valve 3. Conversely, when the power is turned off, the restoring force of spring 4 causes valve 3 to open.
is closed. Therefore, as long as this solenoid valve A operates, the magnetic flux lines generated in the excitation coil 1 will sufficiently magnetize the ferromagnetic cap 5 provided to cover the excitation coil 1. , forming a closed magnetic circuit. In other words, if the cap of the solenoid valve for the magnetic circuit made of ferromagnetic material is arranged in a shape that surrounds the excitation coil, all the magnetic flux lines generated there will be absorbed by the cap, and the movable iron of the solenoid valve will be absorbed by the cap. This means that a closed strong magnetic circuit for lifting the core is formed in this cap, and at the same time, it also means that the leakage of the generated magnetic flux lines to the outside of the cap is not allowed. However, this is just a principle of magnetic shielding, and is not actually the case. Leakage of magnetic flux lines passing through the cap is caused by, for example, overcurrent consumed during the start-up operation of a solenoid valve, and the voltage during normal operation is It is a well-known fact that it occurs regardless of the degree of change, even if it is due to changes, etc., and if there is even a slight leakage of magnetic flux from a solenoid valve, it has been frequently used in recent developments. It is a clear fact that when placed in close proximity to or combined with IC elements or electronic elements, a completely inconvenient situation can occur, and this can cause related IC equipment and electronic equipment to malfunction. Therefore, Japanese Utility Model Publication No. 49-7969 proposes a solenoid valve in which the space inside the cap and its outer periphery are integrally cast-coated with epoxy resin or the like. However, since this electromagnetic valve is coated with resin, it is impossible to disassemble and repair it.

Therefore, as a result of various studies in view of the above circumstances, the present invention has been developed to confine the above magnetic flux leakage to the outside in the magnetic circuit when the magnetic flux is constant, regardless of whether the solenoid valve is for direct current or alternating current. Another object of the present invention is to provide a cap for a solenoid valve that is capable of extinguishing leaking magnetic flux by converting it into a current due to electromagnetic induction within a conductor when the magnetic flux is changing sequentially. The gist is that in a cap made of ferromagnetic material that surrounds the excitation coil part of a solenoid valve and forms the magnetic flux lines generated therein into a closed magnetic circuit, a diamagnetic material is used on the upper surface of the cap. The upper surface layer is made of a highly conductive metal layer such as gold, silver, or copper.

Hereinafter, one embodiment of the present invention will be described based on the drawings. First, as shown in FIG. 1, everything except the cap 5 is a conventionally known direct-acting solenoid valve A, and the excitation coil 1 is wound around a bobbin 6 held by a cylindrical plunger guide 8. A movable iron core 2 is fitted into the cylindrical space so as to be slidable in the vertical direction. Next, 3 is a valve, which is provided at the lowest part of the movable iron core 2, and the valve body A ₁
The plunger guide 8 is connected to the valve body via the plunger guide holder 9 in order to open and close the fluid (arrow D) flowing from the inlet B to the outlet C at the valve hole 7, and to ensure smooth opening and closing operations. It is installed in _A1 . The reference numeral 4 is a spring, and one end of the spring is attached to a core 10 provided as a plug in the upper part of the cylindrical space of the plunger guide 8, and the other end is attached to the movable iron core 2 at the same time. The iron core 2 is urged downward and the opening/closing operation of the valve is controlled. 11
is the lead wire. As shown in FIG. 2, the cap 5 is formed in two layers 5a and 5b in cross section, and the inner layer 5a is made of a ferromagnetic material layer typically made of iron, which is conventionally used as a cap. The outer upper surface layer 5b is coated with a diamagnetic material (sometimes referred to as a non-magnetic material) such as copper. In this case, the upper surface layer 5b is coated with a copper layer, but other materials such as gold and silver may also be used. Further, in this case, the cross-section is formed into two layers, but it is also effective to interpose a gap or other magnetic shielding material between the two layers, and the cross-section is not limited to two layers.

Next, the functions and effects of the present invention having the above configuration will be explained. First, cap 5 of this solenoid valve.
When a magnetic flux is provided in a solenoid valve that operates in response to direct current, the magnetic flux leaking from the inner layer 5a is considered to be constant except when the solenoid valve starts up or when the voltage changes. The magnetic flux is returned to the inner layer 5a, which operates as a magnetic circuit, and no loss occurs in the magnetic flux in this magnetic circuit, and leakage of magnetic flux is sufficiently prevented. That is, this leads to a reduction in the amount of winding of the excitation coil, making it possible to make the solenoid valve more compact. In addition, when this is installed in a solenoid valve operated by alternating current, or when a sudden change occurs in the leaked magnetic flux lines such as at the rise of a direct current solenoid valve as described above, the upper surface 5b of this cap 5 is Therefore, if the upper surface layer 5b is grounded, the upper surface layer 5b will definitely provide magnetic shielding.

Therefore, the cap of the solenoid valve of the present invention can sufficiently suppress or shield some kind of magnetic flux (wire) that sometimes leaks from the inner layer of ferromagnetic material that constitutes the magnetic circuit, and can prevent electromagnetic The practical effects are revolutionary, as there is no effect on nearby ICs or electronic equipment even when the valve operates.

[Brief explanation of drawings]

FIG. 1 is an internal explanatory view of a conventionally known solenoid valve equipped with a solenoid valve cap according to the present invention, and FIG. 2 is a sectional view of the solenoid valve cap. Reference numbers in the drawings: 1...excitation coil, 2...movable iron core, 3...valve, 4...spring, 5...cap, A
……solenoid valve.

Claims (1)

[Scope of utility model registration request] It is attached to a solenoid valve that includes an excitation coil 1, a core 10 disposed above the cylindrical space of the excitation coil 1, and a movable iron core 2 slidably disposed below the cylindrical space. , a cap 5 that surrounds a portion of the excitation coil 1 and forms magnetic flux lines generated therein into a closed magnetic circuit.
It has a laminated structure of layers, and the inner layer 5a is made of a ferromagnetic material such as iron, and the upper surface layer 5b is made of a diamagnetic material made of a metal conductor with high electrical conductivity such as gold, silver, or copper. A solenoid valve cap featuring: