JP3326736B2 - Latch type solenoid 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 latch-type solenoid valve having a permanent magnet and an electromagnetic coil, wherein a plunger connected to a valve element is attracted to a core by the magnetic force of the permanent magnet to attract and hold the valve in an open state.

[0002]

2. Description of the Related Art A conventional latch-type solenoid valve of this type includes a valve body for closing a valve port at the tip of a plunger. A rear end of the plunger is opposed to a permanent magnet with a spring interposed therebetween. Surrounded by electromagnetic coils. When the rear end of the plunger is attracted to the permanent magnet, the valve body is separated from the valve port and is in an open state. In this state, the spring provided between the permanent magnet and the rear end of the plunger is compressed, but the rear end of the plunger does not separate from the permanent magnet because the attractive force of the permanent magnet is stronger than the urging force of the spring.
When the electromagnetic coil is energized so that a magnetic flux in the opposite direction to the magnetic flux of the permanent magnet is generated, the magnetic force of the permanent magnet is canceled by the magnetic force of the electromagnetic coil, and the plunger is separated from the permanent magnet by the urging force of the spring, and the valve body opens the valve port. Closed and closed.
Even if the energization of the electromagnetic coil is stopped in this state, the plunger will not be attracted to the permanent magnet against the urging force of the spring because the permanent magnet is separated from the rear end of the plunger. When the valve is opened, the electromagnetic coil is energized in the direction opposite to the direction when the valve is closed, a magnetic flux is generated by the electromagnetic coil in the same direction as the magnetic flux of the permanent magnet, and the plunger is moved by the permanent magnet against the urging force of the spring. To be absorbed. When the plunger is attracted to the permanent magnet again, the plunger does not separate from the permanent magnet even if the energization of the electromagnetic coil is subsequently stopped as described above. The plunger may be directly attracted to the permanent magnet. However, in general, a core for guiding magnetic flux is brought into contact with one magnetic pole of the permanent magnet so that the plunger is attracted to the core. Further, a frame is provided for efficiently guiding magnetic flux from the other magnetic pole of the permanent magnet to the outer peripheral surface of the plunger. Accordingly, assuming that the other magnetic pole of the permanent magnet is an N pole, the magnetic flux passes through the frame from the outer peripheral surface of the plunger to the rear end of the plunger, passes through the core, and returns to the S pole, which is one of the permanent magnets.

[0003]

In the operation of the on-off valve, for example, when the valve is closed, the electromagnetic coil generates a magnetic flux in the opposite direction to the magnetic flux generated by the permanent magnet as described above. Must penetrate the permanent magnet against the magnetic flux of the permanent magnet. However, since the magnetic flux in the opposite direction due to the electromagnetic coil hardly penetrates the permanent magnet, it is desired that the magnetic flux passage area of the permanent magnet be widened so that a large amount of magnetic flux from the electromagnetic coil penetrates. On the other hand, if the magnetic flux passage area of the permanent magnet is increased, the amount of magnetic flux generated from the permanent magnet increases, and the attraction force to the plunger increases.
Therefore, in order to close the valve by overcoming the magnetic force of the permanent magnet, it is necessary to increase the number of windings of the electromagnetic coil or increase the energizing current value. There is an adverse effect that the plunger is attracted to the permanent magnet and the closed state cannot be maintained.

[0004] In view of the above problems, it is an object of the present invention to provide a latch-type solenoid valve which does not cause the above problems even if the magnetic flux passage area of the permanent magnet is increased.

[0005]

In order to solve the above-mentioned problems, the present invention comprises a permanent magnet and an electromagnetic coil, and a plunger connected to a valve element is attracted to a core by the magnetic force of the permanent magnet.
In a latch-type solenoid valve that sucks and holds the valve in the open state,
From the permanent magnet through the frame, plunger and core
While forming a magnetic flux path returning to the permanent magnet , the core
It is composed of a central shaft part and a top peripheral part with a T-shaped cross section.
The frame has legs and is longer than the distance between the legs.
Contact the outer periphery of the upper end of the core with the legs of the frame.
Thus, a bypass portion for passing a part of the magnetic flux between the frame and the core to bypass the plunger is formed.

[0006]

When the magnetic coil is energized to weaken the attraction force of the plunger to the core, the magnetic flux of the permanent magnet is increased even if the magnetic flux passage area of the permanent magnet is increased so that the magnetic flux of the electromagnetic coil easily penetrates the permanent magnet. Since the part does not flow to the plunger through the bypass part, the attraction force of the plunger to the core can be prevented from increasing more than necessary even if the magnetic flux passage area of the permanent magnet is increased.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to FIG. 1, reference numeral 1 denotes a latch-type solenoid valve, which has a plunger 2 which is held so as to be vertically reciprocable in the drawing. A valve body 21 made of a flexible material such as rubber is fitted to the lower end of the plunger 2. Further, a disc-shaped permanent magnet 3 is arranged on the solenoid valve 1 coaxially with the plunger 2. In the case of the present embodiment, the permanent magnet 3 is mounted such that the upper side is the north pole and the lower side is the south pole. The core 4 is attached to the S pole of the permanent magnet 3, and the upper end 22 of the plunger 2 is attracted to the lower end 41 of the core 4. On the other hand, a frame 5 formed by bending a belt-like steel material is attached to the N pole. The magnetic flux generated from the N pole of the permanent magnet 3
The magnetic path flows through the inside, flows to the outer peripheral surface of the plunger 2 via the base plate 51 and the magnetic plate 52 attached to the lower end, and returns from the upper end 22 of the plunger 2 to the S pole of the permanent magnet 3 through the core 4. You. A thin-walled magnetic pipe 53 made of a magnetic material is attached to the upper surface of the magnetic plate 52, and the magnetic pipe 53 faces the outer peripheral surface of the plunger 2,
Flux that has flowed through the legs of the frame 5, through a magnetic path flowing from the magnetic pipe 53 to the outer peripheral surface of the plunger 2 other magnetic path flowing from the base plate 51 and magnetic plate 52 to the outer peripheral surface of the plunger 2, The magnetic flux was allowed to flow to the plunger 2 effectively.

An electromagnetic coil 6 surrounds the plunger 2.
Is provided. When the electromagnetic coil 6 is energized to generate a magnetic flux having a flow direction opposite to the flow direction of the magnetic flux by the permanent magnet 3, the attractive force of the permanent magnet to the lower end 41 of the core 4 and the upper end 22 of the plunger 2 decreases. . A coiled spring 7 is mounted between the core 4 and the plunger 2. When the electromagnetic coil 6 is energized and the attraction force is reduced, the urging force of the spring 7 overcomes the attraction force and moves the plunger 2 downward. To close the valve port H with the valve element 21.
FIG. 2 shows a closed state in which the valve port H is closed. When the upper end 22 of the plunger 2 moves away from the lower end 41 of the core 4 in this way, the plunger 2 cannot be pulled up only by the magnetic force of the permanent magnet 3 even if the energization of the electromagnetic coil 6 is stopped. Will be retained. Next, when the valve port H is opened from the state shown in FIG. 2, the electromagnetic coil 6 is energized in a direction opposite to the energizing direction at the time of closing the valve, and the electromagnetic coil 6 and the magnetic flux of the permanent magnet 3 Generate magnetic flux in the same direction. Then, the magnetic flux acting between the upper end 22 of the plunger 2 and the lower end 41 of the core 4 increases. Then, the plunger 2 is pulled up against the urging force of the spring 7, and the upper end 22 of the plunger 2 is attracted to the lower end 41 of the core 4 to return to the state shown in FIG. As described above, when the upper end 22 is attracted to the lower end 41 again, the valve open state is maintained even if the energization to the electromagnetic coil 6 is stopped. Reference numeral 11 denotes a guide pipe made of a non-magnetic material.

In order to weaken the attraction force of the plunger 2 to the core 4 when the electromagnetic coil 6 is energized and the valve is closed, or to move the plunger 2 toward the core 4 when the valve is opened,
The magnetic flux generated by the electromagnetic coil 6 needs to penetrate the permanent magnet 3, but the magnetic flux hardly penetrates especially in the permanent magnet 3 made of a ferrite-based material. Therefore, in the present embodiment, the area of the magnetic flux path is increased by increasing the area of both poles of the permanent magnet 3 so that the magnetic flux of the electromagnetic coil 6 can easily pass through the permanent magnet 3. On the other hand, since the magnetic flux of the permanent magnet 3 is proportional to the area of both poles, the magnetic force of the permanent magnet 3 becomes strong when the magnetic flux passage area is increased in this way. As a result, the plunger 2 does not separate from the core 4 and does not close unless a stronger current flows through the electromagnetic coil 6. Even when the valve is closed and the state shown in FIG. 2 is reached, if the magnetic force of the permanent magnet 3 is strong, the
The plunger 2 may be lifted by the magnetic force, and the plunger 2 may not be held in the closed state.

Accordingly, in the present invention, a bypass portion 42 that contacts the frame 5 is formed in a part of the core 4. Referring to FIG. 3, the magnetic flux P generated from the N pole of the permanent magnet 3 flows in both legs of the frame 5 downward, but approaches the bypass portion 42 part of the magnetic flux PE flux P is a bypass portion 42 Return to S pole immediately after passing. Then, the remaining magnetic flux PP flows toward the base plate 51 so as to flow to the plunger 2.
Therefore, since the magnetic flux that causes the plunger 2 to be attracted to the core 4 is PP smaller than P, even if the magnetic flux passage area of the permanent magnet 3 is increased, the magnetic force acting on the plunger does not increase, and the above-described adverse effects do not occur. Next, the electromagnetic coil 6 is closed to close the valve.
When energized, but the magnetic flux C is increased the legs of the frame 5 caused by the electromagnetic coil 6, part of the magnetic flux CE approaches the bypass portion 42 flows directly core 4 through the bypass portion 42, the remaining flux CP The magnetic flux wraps around the permanent magnet 3, penetrates from the N pole side to the S pole side of the permanent magnet 3, merges with the branched magnetic flux CE, and flows to the plunger 2. As a result, the attraction force to the plunger 2 is reduced as described above, and the plunger 2 is lowered to the valve closing position by the urging force of the spring 7. When opening the valve, as described above, the electromagnetic coil 6
When a current is supplied in the opposite direction, a magnetic flux in the same direction as the magnetic flux of the permanent magnet 3 is generated by the electromagnetic coil 6 and penetrates from the S pole side to the N pole side of the permanent magnet 3. The plunger 2 can be pulled up in cooperation with the magnetic flux of the electromagnetic coil 6.

As described above, even if the magnetic force of the permanent magnet 3 is increased by enlarging the magnetic flux passage area of the permanent magnet 3, no adverse effect occurs because the bypass portion 42 is formed. still,
To adjust the amount of magnetic flux bypassed through the bypass portion 42, the contact area between the core 4 and the frame 5 in the bypass portion 42 may be increased or decreased. However, when the core 4 is sandwiched between the frames 5, if the dimension of the portion where the core 4 is sandwiched becomes slightly smaller, a gap is formed between the core 4 and the frame 5 to increase the magnetic resistance. Is greatly reduced. Therefore, as shown in FIGS. 1 and 4, the core 4 has a T-shaped vertical cross section,
The outer periphery D of the core 4 is formed so that the outer diameter D of the upper end outer periphery of the core 4 is larger than the distance L between the two legs of the frame 5, and two opposing outer periphery portions of the upper end of the core 4 are cut off to form a flat portion. 43, the end portion 43a of the flat portion 43 is brought into contact with the frame 5, and the portion near the end portion 43a is
I tried to be. With this configuration, even if a slight dimensional error occurs, the magnetic resistance between the core 4 and the frame 5 hardly changes, and the amount of magnetic flux passing through the bypass portion 42 can be kept constant.

[0012]

As is apparent from the above description, according to the present invention, since the bypass portion is provided between the core and the frame,
The magnetic flux path area of the permanent magnet is expanded to make it easier to pass the magnetic flux generated by the electromagnetic coil. It is possible to prevent the adverse effects caused by the occurrence.

[Brief description of the drawings]

FIG. 1 is a sectional view of an electromagnetic valve 1 in an open state.

FIG. 2 is a sectional view of the solenoid valve 1 in a closed state.

FIG. 3 is an enlarged view showing details of a bypass unit.

FIG. 4 is a sectional view taken along line IV-IV.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Solenoid valve 2 Plunger 3 Permanent magnet 4 Core 5 Frame 6 Electromagnetic coil 42 Bypass section 53 Magnetic pipe

Continuation of front page (56) References JP-A-6-17962 (JP, A) JP-A-63-72979 (JP, A) JP-A 2-145368 (JP, U) JP-A 5-34374 (JP) , U) (58) Fields surveyed (Int. Cl. ⁷ , DB name) F16K 31/06-31/11

Claims (1)

(57) [Claims] A permanent magnet and an electromagnetic coil are provided, and a plunger connected to a valve body is attracted to a core by a magnetic force of the permanent magnet.
Then, in the latch-type solenoid valve that attracts and holds the valve in the open state, the permanent magnet passes through the frame, plunger, and core.
To form a magnetic flux path back to the permanent magnet, and the core
Is composed of a central shaft portion and an outer peripheral
The frame has both legs, and the distance between the legs is
Contact the outer periphery of the upper end of the long core with both legs of the frame.
The Rukoto, latching solenoid valve, characterized in that the formation bypass portion that bypasses the plunger by supplying a part of the magnetic flux between the frame and the core.