JPS6410087B2 - - Google Patents

Description

[Detailed Description of the Invention] Industrial Application Field The present invention relates to a self-holding solenoid that is held by the force of a permanent magnet and released from the holding state by external energization, and is particularly used for opening and closing gas circuits. This invention relates to a case where the invention is applied as a driving source for a solenoid valve using a battery as a power source.

Conventional configurations and their problems Since self-holding solenoids do not require external energization to maintain the holding state, they are suitable for applications where heat generation and power consumption due to coil energization are a problem. However, if the power source is a battery, the voltage required to release the self-holding state of the self-holding solenoid must be lower than the battery voltage. When using a self-holding solenoid as a self-holding electromagnetic valve to shut off a gas circuit, a permanent magnet attraction force is required to maintain the valve open state even if a spring is inserted to ensure sufficient shutoff pressure necessary for shutoff. Even under these conditions, reliable shutoff operation must be possible with the battery voltage.

Figure 1 shows a conventional example of a self-holding solenoid. 2 is a sectional view taken along the line A--A in FIG. 1. Here, a magnetic pole 102 is fixed to the center of the bottom surface of the U-shaped fixed core 101, and a coil 104 wound around a coil bobbin 103 is provided between the outer periphery of the magnetic pole 102 and the fixed core 101. Fixed core 10
A pair of permanent magnets 105 are positioned on the inner surface of the bending free end side of the magnet 1, magnetized so that the opposing sides have the same polarity, and on the inner side, the outer side surface is in contact with the inner surface of the permanent magnet 105, and the center A laminated iron core 106 consisting of a large number of iron plates with round holes formed therein is fixed. These laminated iron core 106 and coil bobbin 10
3 are arranged concentrically, and both ends are engaged by a guide tube 108 together with a stopper 107. A movable core 109 is inserted into the guide tube 108 so as to be freely movable in the axial direction. With the above configuration, the coil bobbin 103, the laminated iron core 106, and the stopper 107 are integrated by the guide tube 108.
is inserted together with the permanent magnet 105 from the bent open end side of the fixed iron core 101, and finally the stopper 107 is fixed with the free end hooking part 110 of the fixed iron core 101 to complete the process.

This self-holding solenoid has a permanent magnet 105
From laminated iron core 106, movable iron core 109, magnetic pole 10
2. The movable core 109 is attracted toward the magnetic pole 102 by the magnetic flux flowing with the fixed core 101. When the coil 104 is energized, the coil magnetic flux tends to flow in the opposite direction to the magnetic flux of the permanent magnet 105, and as a result, the amount of magnetic flux passing through the contact surface between the movable iron core 109 and the magnetic pole 102 decreases, and the attractive force is drastically reduced. , the movable iron core 109 is separated from the magnetic pole 102 by a spring (not shown). The coil can be energized in a pulse-like instant, and in order to return to the attracted state again, it is sufficient to push the movable core 109 back to the position where it contacts the magnetic pole 102 by overcoming the force of the spring from the outside.

Now, since the load of the spring to be inserted will be large when used to interrupt the gas circuit, the permanent magnet 1
The suction force of 05 is also required to exceed this load. If the length simply increases the force in the attracted and held state, it can be designed freely by selecting the magnet material and magnet area, but when detaching by energizing a battery as a power source, the magnetic flux on the attracting surface is controlled by the current supplied from the battery. Since this must be reduced, consideration must be given to the relationship between the number of coil turns and resistance. That is, when winding on the same coil bobbin, if the diameter of the conductor is made thinner and the number of turns is increased, the current decreases due to the increase in resistance and the number of excitation ampere turns decreases. Also, if the conductor diameter is increased, the resistance decreases, the current increases, and the number of turns decreases, but the excitation ampere turns increases. However, in this case, there is an upper limit to the current that can be supplied without damaging the battery, so it is not possible to use a winding specification with low resistance unnecessarily. That is, when a battery is used as a power source and the coil winding space is constant, it can be seen that there are certain restrictions on the excitation ampere turns that can be supplied naturally. Therefore, if a permanent magnet is required that has an attractive force that overcomes the spring load required for shutoff,
The number of excitation ampere turns required for detachment is also large, and in the case of battery drive, an increase in coil space may be an essential requirement. In this case, in the conventional example shown in FIGS. 1 and 2, the coil bobbin 103
If the solenoid is lengthened in the axial direction, the entire solenoid becomes elongated, which not only requires a long storage space when applied to a valve, but also increases the length of the magnetic path as seen from the permanent magnet 105. This also results in a decrease in suction and holding power. Furthermore, if the coil bobbin 103 is made larger in the radial direction, the distance between the magnets 105 facing each other becomes larger for convenience of assembly, and the outer shape of the laminated iron core 106 becomes larger. Therefore, the magnetic path from the magnet 105 to the movable core 109 becomes long, and the magnetic path from the laminated core 106 to the movable core 109 becomes longer.
This results in an increase in leakage magnetic flux that does not pass through and leaks to the bent portion of the fixed iron core 101, resulting in a decrease in the attraction and holding force.

As described above, the configuration of the conventional example is inappropriate when a self-holding solenoid used for the purpose of interrupting a gas circuit is operated by a battery.

Technical Problems of the Invention The purpose of the present invention is to obtain a self-holding solenoid that can be operated by batteries while ensuring a high attraction and holding force. The structure is such that the necessary excitation ampere-turns are stabilized when the coil is energized and removed.

Technical Means of the Invention In other words, an electromagnetic coil wound around a coil bobbin is provided at the center of the bottom surface of a substantially U-shaped fixed core with legs bent symmetrically from the bottom surface, and the electromagnetic coils are arranged with the same polarity at symmetrical positions inside the legs of the fixed core. A pair of permanent magnets are provided so that they face each other, and a movable iron core is provided so as to be able to slide freely through the gap between the permanent magnets and the center hole of the coil bobbin.
A magnet holder is provided, which is formed around a guide hole that guides the sliding movement of the movable core, and holds a permanent magnet in contact with the inside of the leg of the fixed core, and the movable core has a cylindrical portion facing the coil bobbin center hole, and a magnet holder. The portion facing the guide hole is prismatic, and the coil bobbin and magnet holder have positioning portions formed on both so that the centers of the center hole and the guide hole coincide with each other.

Effect of the Invention Therefore, since the coil bobbin and the magnet holder can be separated, it is possible to select the outer diameter of the coil bobbin regardless of the distance at which the magnets face each other. Since there is no gap between the opposing and intermediate magnetic circuit members, the leakage magnetic flux of the permanent magnet is reduced. In addition, the inclination of the movable iron core in the suction and holding state has a large effect on the attraction force and the variation in excitation ampere turns required for detachment, but in the present invention, the centers of the center hole and the guide hole are aligned, and Since the movable iron core is slidably supported by the rectangular guide hole of the magnet holder that is located away from the attraction surface, the inclination that occurs in the gap in this area can be reduced. Therefore, while having a strong adsorption and holding force, it is possible to operate reliably and without variation using low power such as that of a battery.

Configuration of Examples Next, the present invention will be explained in detail based on Examples. FIG. 3 shows one embodiment, and shows a top view, a vertical sectional view, and a right side view. Furthermore, Figure 4 shows the third
FIG. 3 is an external view showing a part of the embodiment shown in the figure.

Here, 1 is a leg 3 bent symmetrically from the bottom 2.
It is a substantially U-shaped fixed iron core having a magnetic pole 4 fixed to the center of the bottom surface 2. Next, an electromagnetic coil 6 wound around a coil bobbin 5 is provided in the space created by the bottom surface 2 and the legs 3. coil bobbin 5
is positioned by the center hole 7 fitting into the magnetic pole 4, and a rectangular positioning protrusion 8 is formed at the upper end to determine the position with a magnet holder, which will be described later. On the other hand, near the end of the leg portion 3, a pair of permanent magnets 9 are located on the inner surface of the leg portion 3 so that opposite sides thereof have the same polarity. The permanent magnet 9 is held in position by a magnet holder 10,
The center of the magnet holder 10 has a rectangular guide hole 1 that passes through it.
1, and a magnet holder 12 is provided on the side surface of the flat magnet 9, leaving only the side in contact with the leg 3 and enclosing the rest, and the magnet 9 is housed in an angular recess 13. Furthermore, the magnet holder 10 itself has a claw portion 14 at the upper end.
This is fitted into the wedge-shaped groove 15 at the end of the leg 3 of the fixed iron core 1 and then heat-sealed and fixed. On the other hand, a positioning protrusion 16 is formed at the lower end to fit into a rectangular positioning protrusion 8 on the upper end of the coil bobbin 5. In this way, the coil bobbin 5 and the magnet holder 10 are stacked on the same axis, and the central part 7 of the coil bobbin 5
The center lines of the guide hole 11 of the magnet holder 10 also coincide with each other. Now, the movable iron core 17 slides through these holes, the part that goes in and out of the coil bobbin center hole 7 is a cylinder 18, and the part that goes in and out of the magnet holder guide hole 11 is a rectangular pillar 19. It's summery.

Now, the magnetic flux of the permanent magnet 9 crosses the guide hole 11 of the magnet holder 10 and directly passes through the long rectangular column 1 of the movable iron core 17.
9, from the cylinder 18 to the magnetic pole 4, to the bottom surface 2 of the fixed iron core 1, and from the leg 3 to the permanent magnet 9. Movable iron core 1
The attraction and holding force for the magnetic pole 7 is exerted between the lower end surface of the cylinder 18 and the upper end surface of the magnetic pole 4 . When the electromagnetic coil 6 is energized, a magnetomotive force acts in the opposite direction to the magnetic circuit described above, reducing the amount of magnetic flux on the attraction surface. Therefore, the attraction and holding force is drastically reduced, and the movable iron core 17 is separated from the magnetic pole 4 by an external force such as a spring (not shown).

In the example shown in the right side view of FIG. 3, the coil bobbin 5 is inserted by lifting it upward by the thickness of the magnetic pole 4 from the right side, and then lowering it downward so that the magnetic pole 4 fits into the center hole 7. On the other hand, in the magnet holder 10, the pair of magnets 9 are inserted from above to below the legs 3 with the recesses 13 accommodated, and the positioning protrusions 8
and 16 are engaged, and then press the claw part 14
Complete by heat fusing. Therefore, since the insertion directions of the two are different, the outer diameter of the coil bobbin 5 is not restricted by the distance across opposite sides of the leg portion 3, so that a sufficient coil space can be secured. Therefore, by increasing the number of turns within the range of current that the battery can tolerate, it is possible to design a battery to ensure sufficient ampere turns for operation. Further, since the inner magnetic path facing the magnet 9 is a prismatic movable core 17, leakage within the fixed side magnetic circuit can be suppressed to a small extent. Furthermore, since the thickness of the magnetic pole 4 cannot be made too thick in view of the coil bobbin insertion, there is a concern that magnetic flux that does not contribute to the attractive force leaks from the leg portion 3 of the fixed core 1 to the cylinder 18 of the movable core 17. Since the distance between the opposite sides of the legs of the coil bobbin insertion part is set wider than the distance between the opposite sides of the legs of the magnet part, leakage magnetic flux from this part can also be reduced. Next, the state of close contact between the magnetic pole 4 and the end face of the movable core 17 has a large effect on the adsorption holding force and the variation in operating ampere turns, but the close state is influenced more by the inclination of the movable core than by the surface roughness during machining. big. Since the present invention uses a movable iron core with an irregular cross section, it is not possible to provide a non-magnetic guide pipe along the entire length as in the conventional example, but it is slidably supported by the guide hole 11 of the magnet holder 10 located away from the attraction position. In particular, the inclination caused by the gap between the movable iron core 17 and the guide hole 11 is reduced.

FIG. 5 is a longitudinal sectional view showing an example in which a self-holding solenoid according to an embodiment of the present invention is applied to a gas cutoff valve. The self-holding solenoid 20 is similar to the example shown in FIG. 3, but a valve shaft 21 is screwed to the top of the movable core 17, and a valve rubber 22 is inserted into the valve shaft 21, which closely contacts the valve shaft 21 in the radial direction. In the figure, a valve plate 23 is provided on the lower surface. On the other hand, a mounting flange 24 is fixedly welded to the leg portion 3 of the fixed iron core 1, and a spring 26 is inserted between the spring receiver 25 provided thereon and the valve plate 23. With the above steps, the valve body is completed, and this is installed into the valve housing 26. The valve housing 26 has connecting holes 27 and 28, and a valve seat 29 is provided between the connecting holes 27 and 28, and corresponds to the valve rubber 22 described above. One side of the mounting flange 24 of the valve body is fixed with a screw, and the other side is inserted into a groove 30 provided in the valve housing 26 to determine its position. After the valve body is housed in the valve housing 26, it is hermetically sealed with a bottom plate 31. Furthermore, 32 is a valve opening shaft, and a cam 33 that rotates together with this shaft contacts the flat surface of the top of the valve shaft 29 and moves it in a linear direction by rotation.

Effects of the Embodiment In the above configuration, when a pulse current is applied to the electromagnetic coil 6 when some abnormal condition occurs and it is necessary to shut off, the attraction and holding force by the permanent magnet 9 is drastically reduced, so the spring 26 The movable iron core 17 is separated from the magnetic pole 4 by the force of the valve rubber 22,
It moves upward together with the valve stem 21 to shut off the gas passage. At this time, since the valve rubber 22 has a structure that allows some oscillation around the part in close contact with the valve shaft 21 in the radial direction, the perpendicularity of the operating axis of the movable iron core 17 with respect to the valve seat 29 may be slightly At worst, occlusion can be ensured. Next, when the valve opening shaft 32 is rotated counterclockwise, the cam 33 and the flat top surface of the valve shaft 29 come into contact, overcoming the spring 26 and pushing down the entire valve, to the cam position shown by the dotted line in FIG. Then, the movable iron core 17 attracts and holds the valve again, and the valve opens.

In this case, chips mixed into the gas piping during pipe work and iron powder due to rust on the gas pipes may come along with the gas flow and reach the shutoff valve. When these magnetic powders are attracted around the permanent magnet 9, leakage magnetic flux that does not pass through the attracting surfaces of the movable iron core 17 and the magnetic pole 4 increases, causing a decrease in the attraction and holding force. In this regard, in the conventional configuration shown in FIG. 1, the side surface of the permanent magnet 106 is exposed as shown in the right side view, so magnetic powder tends to be attracted at this time and leakage does not contribute to the attraction force. Magnetic flux will increase. However, since the magnet holder 10 shown in FIG. 4 wraps around the permanent magnet 9, it becomes difficult for the magnetic powder to be attracted to it, and even if it does, it will be located far away from the main body of the permanent magnet 9. The extent to which leakage magnetic flux is increased is small. In this way, there is an effect that the reduction in suction and holding power can be reduced even when iron powder or the like adheres from the outside.

Effects of the Invention As described above, the present invention provides an electromagnetic coil on the bottom of a substantially U-shaped fixed core, a pair of permanent magnets on the inner surface of the legs, and a space between the permanent magnets and a central hole of the electromagnetic coil. A movable iron core that can be freely slid through is provided, a guide hole is formed to guide the sliding movement of the movable iron core, and a magnet holder is provided to hold a permanent magnet on the inner surface of the leg. The part facing the center hole of the coil bobbin is prismatic and has a cylindrical shape, and the movable core is a self-holding solenoid with the prismatic part slidingly guided by the rectangular guide hole of the magnet holder. By being divided, the outer diameter of the coil bobbin is no longer restricted by the distance between the opposite sides between the permanent magnets, and a complete guide portion is formed for the sliding movement of the movable iron core. Therefore, sufficient ampere turns can be ensured even in the case of a power source such as a battery that has a low voltage and has a limited upper limit value of supply current. Furthermore, since there are fewer elements that produce leakage magnetic flux that is not useful for attracting and holding the movable core, a high attracting and holding force can be obtained. Therefore, it is expected that the operational reliability of the self-holding solenoid will be improved.

Furthermore, since the coil bobbin and magnet holder are separated, ease of assembly is improved, and because there are fewer magnetic circuit components and the tilt of the movable core is small, the attraction and holding force and the excitation required for detachment are improved. Variations in ampere turns can also be reduced.

In addition, self-holding solenoids sometimes use a method of detecting the return operation from the release position to the holding position using the instantaneous electromotive force generated in the electrode coil, but in the present invention, a high electromotive force value can be obtained. It's also effective. Conventionally, a non-magnetic but conductive guide tube was used to reduce the inclination of the movable core. This causes a warming effect, which causes the electromotive force value to decrease. Since the present invention does not have such a guide tube, sufficient electromotive force can be obtained, and the system has the effect of increasing reliability.

[Brief explanation of drawings]

Figures 1a, b, and c show a top view, front view, and cross-sectional view of a conventional solenoid, and Figure 2 shows A--A in Figure 1.
A sectional view taken along the line A, FIGS. 3a, b, and c are top views, sectional views, and side views of a self-holding solenoid showing one embodiment of the present invention. FIG. 4 is a perspective view of the coil bobbin and magnet holder shown in FIG. 3. FIG. 5 is a longitudinal cross-sectional view of a self-holding solenoid according to an embodiment of the present invention applied to a gas cutoff valve. 1...Fixed iron core, 2...Bottom surface, 3...Legs, 5
... Coil bobbin, 6 ... Electromagnetic coil, 7 ... Coil bobbin center hole, 8, 16 ... Positioning part, 9
... Permanent magnet, 10 ... Magnet holder, 11 ... Guide hole, 12 ... Permanent magnet holding part, 17 ... Movable iron core.

Claims (1)

[Scope of Claims] 1. A substantially U-shaped fixed core with legs bent symmetrically from the bottom, an electromagnetic coil provided at the center of the bottom of the fixed core and wound with a coil bobbin, and a symmetrical inner leg of the fixed core. A pair of flat permanent magnets with the same polarity facing each other, a movable iron core that is slidably provided through the gap between the permanent magnets and the center hole of the coil bobbin, and a square-shaped permanent magnet that guides the sliding movement of the movable iron core. A magnet holder has a guide hole in the center and holds the pair of permanent magnets in contact with the inner surface of the fixed core legs, and the movable core has a cylindrical portion facing the coil bobbin center hole to guide the magnet holder. The self-holding solenoid has a prismatic portion facing the hole, and a positioning portion is formed on both the coil bobbin and the magnet holder so that the center of the center hole and the guide hole are aligned with each other. 2. The self-holding solenoid according to claim 1, wherein the leg portion of the fixed core has a distance across opposite sides narrower at the permanent magnet portion than at the electrode coil portion.