JPS6335878B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a pilot type two-port solenoid valve.

[Conventional technology] Conventionally, the pressure difference between the primary side pressure and the secondary side pressure was almost 0.
A pilot type 2-port solenoid valve that can operate even in the case of 1988-5823, for example, has a pilot valve that opens and closes the pilot discharge hole on the main valve, which is attached to a movable iron core. The stroke of the movable core opens the pilot valve and then opens the main valve connected to the movable core via a spring.

However, in the above conventional solenoid valve, the main valve is opened after the pilot valve seat is opened by the movable iron core. Therefore, when the main valve is in the open position, the movable iron core opens the main valve and the main valve is opened at the same time. The pilot valve seat on the valve is at a position where the stroke is enough to open it, that is, the stroke amount of the movable iron core is the sum of the stroke amount of the main valve and the stroke amount of the pilot valve, and the stroke amount of the movable iron core is to be less than that. I couldn't do it.

[Problems to be solved by the invention] The electromagnetic operation part of the electromagnetic valve as described above is
If the stroke of the movable iron core is small, the capacity of the electromagnetic operating section can be reduced accordingly, that is, the electromagnetic operating section can be made smaller and less expensive, and the product can be obtained at a lower price.

The present invention provides a pilot-type two-port solenoid valve in which the pilot valve is opened in the latter half of the suction stroke when the electromagnetic force acting on the movable core becomes large, thereby further reducing the size of the solenoid operating section.
The problem to be solved is to operate even with zero differential pressure.

[Means for Solving the Problems] The present invention provides a main valve seat on which the main valve approaches and separates the passage between the inlet port and the outlet port opened in the valve body, and a pilot seat behind the main valve. A pressure acting chamber is provided which communicates with the inlet port and the outlet port through a supply hole and a pilot discharge hole, and a pilot valve driven by a movable iron core of an electromagnetic operating section opens and closes the pilot discharge hole to control the movable pressure chamber. In a pilot type two-port solenoid valve in which a main valve connected to an iron core by a lift spring is brought into contact with and separated from the main valve seat, the pilot discharge hole is fixedly provided in the valve body, and the pilot discharge hole of the pilot discharge hole is fixedly provided in the valve body. A pilot valve that approaches and separates from a valve seat is attached to a movable iron core with a spring biased toward the valve closing direction, and the movable iron core engages with the pilot valve in the latter half of the suction stroke in which the movable iron core is attracted to the fixed iron core. The above problem is solved by providing an engaging portion.

[Function] When the fixed core attracts the movable core by energizing the electromagnetic coil, if the differential pressure between the primary pressure and the secondary pressure is almost 0, the attraction force causes the main force to flow through the lift spring. The valve is opened, but if the above differential pressure exists to some extent, the movable core is attracted to the fixed core against the urging force of the lift spring, and when the attraction force becomes large in the latter half of the attraction stroke. , the engaging portion of the movable iron core engages with the pilot valve, opening the pilot discharge hole. When the pilot discharge hole opens, the fluid in the pressure chamber flows out through the pilot discharge hole to the outlet port, and the pressure in the pressure chamber decreases, so the main valve is opened by the fluid pressure from the inlet port. .

When the power to the electromagnetic coil is cut off, the movable core returns and the pilot valve closes the pilot valve seat due to the biasing force of the spring, so the fluid pressure in the pressure action chamber increases and the main valve closes the main valve seat. Close.

[Embodiment] FIG. 1 shows a first embodiment of the present invention, in which a valve body 1
has a main valve seat 4 that forms a valve opening in an inlet port 2, an outlet port 3, and a passage therebetween, and a main valve 5 facing the main valve seat 4 has a diaphragm 5a.
It is supported in the valve body 1 by a pressure chamber 6 behind which a pressure acting chamber 6 is formed.

The pressure action chamber 6 is communicated with the outlet port 3 through a pilot discharge hole 8 provided in the valve body 1, and a pilot supply hole 10 having a smaller diameter than the pilot discharge hole 8 is bored in the diaphragm 5a. , whereby the pressure chamber 6 is communicated with the inlet port 2 .

An electromagnetic operating section 20 is fixed to the upper part of the valve body 1 so that the movable iron core 23 is attracted to the fixed iron core 22 by turning on and off the current to the electromagnetic coil 21 . The movable iron core 23 of the electromagnetic operation section is connected to the main valve 5
A pilot valve accommodating chamber 25 is formed inside the cylinder part 24, and the pilot valve 27 is slidably biased by a travel spring 26 in a direction to close the pilot valve seat 7. An engaging portion 25a is formed on the edge of the pilot valve accommodating chamber 25 to engage with the pilot valve 27 and prevent it from escaping.

Further, on one side of the cylindrical portion 24 of the movable core 23, as shown in FIGS. 2A and B, a notch 2 is provided.
A pilot discharge hole 8 of the valve body is introduced through the notch 24a, and the pilot valve seat 7 is opened at a position opposite to the pilot valve 27.

The engagement portion 25a with the pilot valve 27 provided on the edge of the pilot valve housing chamber 25 is configured to engage with the pilot valve 27 in the latter half of the suction stroke in which the movable core 23 is attracted to the fixed core 22. When the movable core 23 is urged in the direction of the main valve 5 by the return spring 28 which is disposed between the movable core 23 and the fixed core 22, the return spring 28 engages with the pilot valve 27. A distance corresponding to the travel amount b, which is approximately the same as the main valve stroke c, is formed between the main valve stroke c and the main valve stroke c. On the other hand, the distance between the sill plate 15 attached to the diaphragm 5a by the stopper 14 and the abutting shoulder formed on the inner wall of the pressure action chamber 6 is made equal to the main valve stroke c. Furthermore, the end portions of the lift springs 16 are engaged with the locking steps 14a provided on the stopper 14 and the grooves 23a provided on the lower peripheral edge of the movable iron core 23, respectively.

Next, the operation of the first embodiment will be explained. 1st
In the figure, the electromagnetic coil 21 is in a de-energized state, and the pressure fluid from the inlet port 2 is supplied to the pressure action chamber 6 through the supply hole 10 of the diaphragm 5a, while the pilot valve 27 is connected to the travel spring. Since the pilot valve seat 7 is closed by the urging force at 26, the pressure in the pressure action chamber 6 rises and the main valve 5 closes the main valve seat 4.

When the electromagnetic coil 21 is energized in this state, the fixed core 22 attracts the movable core 23 against the urging force of the return spring 28.
slides while extending the lift spring 16. In this case, if the pressure difference between the primary side and the secondary side is small and the biasing force of the lift spring 16 becomes larger than the valve closing force due to the fluid pressure in the pressure action chamber 6, the main valve 5 is moved by the lift spring 16. and then pulled up to open the main valve seat 4.

If the pressure difference between the primary side and the secondary side is large and the main valve 5 cannot be opened directly by the urging force of the lift spring 16, the movable iron core 23 will be opened by the suction force of the fixed iron core 22. When the movable iron core 23 slides by a distance b, the engaging portion 25a of the movable iron core 23 engages with the pilot valve 27, and as the movable iron core 23 continues to slide, the pilot valve 27 opens the pilot valve seat 7, so that no pressure is applied. The fluid in the chamber 6 flows out through the pilot outlet 8 into the outlet port 3, and the pressure in the pressure application chamber 6 decreases. Therefore, the main valve 5 opens the main valve seat 4 due to the biasing force of the lift spring 16 which is in the expanded state.

In the sliding movement of the movable core 23 described above, the relationship between the stroke, the electromagnetic attraction force, the pilot valve load, and the spring characteristics is shown in FIG. 5A, where the attraction force at the end of the stroke of the movable core 23 is sufficiently large. When the pilot valve 27 is fully seated, the pilot valve seat 7 is opened, so that the attraction force of the electromagnetic coil 21 can be reduced and the electromagnetic operating section 20 can be made smaller compared to the conventional example shown in FIG. .

In other words, as shown in Figure 5B, with conventional solenoid valves, the pilot valve, which has the maximum load, is opened at the beginning of the stroke of the movable core, where the suction force of the fixed core is small, so a large suction force is required at that point. However, the two-port solenoid valve of the above embodiment utilizes the sufficiently large electromagnetic attraction force at the end of the stroke of the movable core 23. Return stroke end (stroke right end in Figure 5 A)
In this case, it is possible to use a small electromagnetic operating portion having an attractive force sufficient to overcome the combined spring force of the lift spring 16 and the return spring 28.

When the electromagnetic coil 21 is de-energized, the movable iron core 23 is moved by the biasing force of the return spring 28.
returns to the valve closing direction, and the pilot valve seat 7 is closed by the pilot valve 27, so the pressure inside the pressure action chamber 6 is increased by the pressure fluid supplied from the pilot supply hole 10 to the pressure action chamber 6. and main valve 5
causes the main valve seat 4 to close. In this case, even if the fluid pressure in the pressure action chamber 6 is low, the main valve 5 closes the main valve seat 4 due to the urging force of the return spring 28, so that the gap between the inlet port 2 and the outlet port 3 is Even if the pressure difference between is small, the valve closing operation is performed reliably.

FIG. 3 shows a second embodiment of the invention, which differs from the first embodiment except that the pilot discharge hole 31 is provided through a stop 32 on the main valve 5. , so the same or equivalent parts will be given the same reference numerals and their explanation will be omitted.

FIG. 4 shows a third embodiment of the present invention, in which the movable iron core 23 in the second embodiment is
Lift spring 1 provided between the main valve 5 and the main valve 5
6, the main valve 5 is urged in the direction of the movable iron core 23 between a locking portion 35a formed by bending the peripheral edge of the shell plate 35 outward and a peripheral portion of the diaphragm 5a in the valve body 1. A stop 37 that moves together with the main valve 5 is provided with a lift spring 36 that moves the main valve 5.
is brought into contact with the movable iron core 23. The other configurations are the same as in the second embodiment.

Lift spring 36 in this third embodiment
The biasing force of the return spring 28 is smaller than that of the return spring 28, and the operation is the same as that of the second embodiment except that the biasing force acts in the direction opposite to the return spring 28 as shown in FIG. 5C. The explanation of is omitted.

[Effects of the Invention] In the present invention, a pilot discharge hole that is opened and closed by a pilot valve is provided in the valve body, which is a fixed part, and the pilot valve opens the pilot discharge hole in the latter half of the suction stroke of the movable iron core. Therefore, even if the electromagnetic part is made small and the attraction force of the electromagnetic coil is small, the pilot valve can open the main valve seat, which reduces the size of the electromagnetic operation part and also reduces the power consumption. Moreover, the valve can be opened and closed even when the fluid pressure is high or when the pressure difference is minute and almost zero.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional front view showing a first embodiment of the present invention, FIG.
Figure B is a vertical cross-sectional view of the same, Figure 3 is a vertical front view of the second embodiment of the present invention, Figure 4 is a vertical front view of the third embodiment of the present invention, and Figures A to C are the movable iron core. These diagrams show the relationship between stroke and suction force. Figure A shows the case of the first and second embodiments of the present invention, Figure B shows the case of the conventional 2-port solenoid valve, and Figure C shows the case of the conventional 2-port solenoid valve. The case of the third embodiment is shown. 1... Valve body, 2... Inlet port, 3... Outlet port, 4... Main valve seat, 5... Main valve, 6... Pressure action chamber, 7... Pilot valve seat, 8, 31... Pilot discharge hole, 10...Pilot supply hole, 1
6, 36... Lift spring, 20... Electromagnetic operation unit, 22... Fixed iron core, 23... Movable iron core, 2
5a...engaging portion, 26...travel spring,
27...Pilot valve.

Claims (1)

[Claims] 1. A main valve seat is provided in the passage between the inlet port and the outlet port opened in the valve body, and a main valve seat is provided for the main valve to move in and out of the passage, and a pilot supply hole and a pilot discharge hole are provided behind the main valve to connect the inlet port and the outlet port. The main valve is provided with a pressure chamber communicating with the port, and the pilot valve is driven by the movable core of the electromagnetic operating section to open and close the pilot discharge hole, and is biased by a lift spring in the direction of the movable core. In the pilot operated two-port solenoid valve, the pilot discharge hole is fixedly provided in the valve body, and the pilot valve, which is connected to and separated from the pilot valve seat of the pilot discharge hole, is closed. It is attached to a movable iron core with a spring bias in the direction of the valve, and is characterized in that the movable iron core is provided with an engaging portion that engages with the pilot valve in the latter half of the suction stroke in which the movable iron core is attracted to the fixed iron core. Pilot type 2
Port solenoid valve.