JPS6283575A - Solenoid valve - Google Patents

Abstract

PURPOSE:To make a solenoid valve to be compact, by making a fixed iron core adsorb a movable iron core, in case of being held a valve member at a position where this valve member opens/closes a valve seat by a spring energizing force, when the differential pressure between the input port side hydraulic pressure and the output port side hydraulic pressure, which act to the movable iron core, becomes lower. CONSTITUTION:A valve seat 9 is formed at the movable iron core 5-side end of an input flow route 7 of a fixed iron core 4, and a valve member 10 is set on the movable iron core 5. A spring 6 is so set as the movable iron core 5 opens the valve, through being pushed by the primary side hydraulic pressure, which acts to the movable iron core 5 in the valve seat 9, when the pressure of the primary side fluid which is fed from the input port through the valve seat 9, is sufficiently higher than the pressure of the secondary side fluid, but the movable iron core 5 closes the valve, when the difference between the fluid pressure of the primary side and that of the secondary side, becomes small. Accordingly, the adsorptive force between the fixed iron core and the movable iron core can be made small, and consequently, the solenoid operated part can be miniaturized.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a solenoid valve used in industrial machinery that utilizes fluid pressure. This relates to a solenoid valve used in applications where the valve closes when the valve becomes small.

[Prior Art] Conventionally, in a solenoid valve, a valve member provided on a movable core always closes the valve seat by the biasing force of a spring, and when the coil is energized, the movable core is attracted to the fixed core and closes the valve seat. A normally closed solenoid valve that opens.

There is a normally closed electromagnetic valve in which the valve member normally opens the valve seat by the biasing force of a spring, but closes the valve seat by attracting a movable core due to hair passing through the coil.

All of these solenoid valves target the coil and attract the moving core when the movable core is at the farthest position from the fixed core, so a large force is required to attract the movable core. As a result, the electromagnetic operation part is too stiff, which not only makes it difficult to downsize the electromagnetic valve, but also has the disadvantage of high power consumption.

Furthermore, since the movable core collides with the fixed core due to the attractive force of the fixed core due to the energization of the coil, there is also the disadvantage that the core is subject to large wear and the life of the solenoid valve is short.

[Problems to be Solved by the Invention] The present invention particularly relates to electromagnetic valves used in applications where the valve only needs to be closed when the fluid pressure difference between the downstream side and the downstream side is small, such as a nozzle valve. A pilot pressure chamber that introduces fluid pressure, or an electromagnetic valve that introduces pressure fluid into a closed space such as a cylinder and closes the valve after the closed space reaches the same pressure as the primary side. In the case of valves, we focused on the fact that the valve member can be connected to a coil (A/C) while the valve member is held at a position close to the closed position. The objective is to obtain a solenoid valve that has a long life.

[Means for Solving the Problems] The present invention has a fixed core fixed in the center hole of a coil, a movable core slidably inserted therein, and a valve member provided at one end of the movable core connected to a double core. In a solenoid valve that closes the valve seat by suction and blocks the flow of fluid, the movable core is provided with a spring that biases it toward the fixed core, and the biasing force of this spring IJ is input. When the pressure of the primary fluid supplied from the port through the valve seat is sufficiently greater than the pressure of the secondary fluid, the movable iron core is pressed within the valve seat by the primary fluid pressure acting on it and opens the valve. However, when the fluid pressure difference between the negative side and the secondary side becomes very small, the movable iron should be set to such an extent that the force will hold the movable iron in the closed position, thereby solving the above problem. It is resolved.

[Function] When the flow to the coil is cut off, the pressure difference between the primary pressure fluid supplied to the input flow path and the secondary pressure fluid of the output wave path is large, and the acting force due to this pressure difference is If the biasing force of the spring acting against the side fluid pressure is greater than the biasing force of the spring, the valve member opens the valve seat and the pressurized fluid in the input flow path flows to the output flow path.

As a result, the fluid pressure at the output port increases, and when the acting force due to the differential pressure between the primary and secondary sides acting on the movable core becomes smaller than the biasing force of the spring, the valve member is moved to the closed position or The movable iron core is also held in a position close to the fixed iron core, so if the coil is energized in this state, the movable iron
Since the distance between the valve seat and the fixed iron core is very small, the valve seat can be closed by a small suction force from a small electromagnetic operating section. Furthermore, since the movable core and the fixed core are almost in contact with each other, the four cores do not accidentally hit each other.

In this state, even if the fluid pressure on the secondary side decreases or disappears,
Since the movable core is attracted to the fixed core with a large suction force, the valve member maintains the valve seat in the closed state.

When the current to the coil is cut off in a state where the fluid pressure at the output port has decreased or disappeared, the valve member opens the valve seat by the fluid pressure from the supply channel, and pressurized fluid is supplied to the output port side.

[Example] Fig. 1 shows an example of a solenoid valve according to the present invention. In this solenoid valve l, a coil made of non-magnetic material with one end closed is inserted into the center hole of a bobbin around which a coil 2 is wound. The fixed iron core 4 is fixed to the open end of the tube 3, and the movable iron core 5 is slidably inserted into the tube 3, and the movable iron core 5 is inserted between the closed side of the tube 3 and the movable iron core 5. , a spooling B is interposed to urge the movable core 5 toward the fixed core 4.

The above r:A constant iron core 4 has 1 at its center position and eccentric position,
! Input flow path 7 and output flow path 8 penetrating in the III line direction
and these channels are communicated with the manual port and the output port as appropriate. Therefore, the movable iron core 5 of the input flow path 7
A valve seat 9 is formed at the side end, and a valve member 10 for opening and closing the valve seat 9 is provided on the end face of the movable iron core 5 facing the side end.

The biasing force of the spring B is set to such an extent that the valve is opened by the fluid pressure on the primary side, that is, the pressure of the primary fluid supplied from the input boat through the valve seat is sufficiently higher than the pressure of the secondary fluid. When the pressure is large, the movable iron core 5 is pressed in the valve seat 9 by the primary fluid pressure acting on it to open the valve, but when the fluid pressure difference between the negative side and the secondary side becomes small, the spring The setting is such that the movable iron core 5 is held in the valve closing position by force.

In addition, in Fig. 1, D is the valve seat, the diameter of 9, P, , P2
indicates the fluid pressure on the primary side and the secondary side, that is, the input flow path 7 and the output flow path 8.

Next, the operation of the above electromagnetic valve will be explained.

FIG. 1 shows a state in which the movable core 5 is attracted to the fixed core 4 by passing through the coil 2, and the valve member 1o closes the valve seat 9.

In this state, even if the pressure P1 of the fluid supplied to the input flow path 7 acts on the valve member 10, the valve seat 9 will not open because it is attracted to the movable iron core 5 or the fixed iron core 4.

When the current to the coil 2 is cut off when the fluid pressure P2 on the output port side has decreased, the force acting in the valve opening direction on the movable iron core 5 due to the differential pressure ΔP between the pressure P and P2, or the force of the spring 6 Since the biasing force f is stronger than the biasing force f, the movable iron core 5 slides in the valve opening direction against the biasing force of the spring 6, and the valve member 1
o opens the valve seat 8. Therefore, is the pressure fluid the input flow path?
, the valve member IO is held in the open state (second (see figure).

The fluid pressure P2 on the output flow path 8 side increases due to the supply of pressure fluid to the desired device, and the force acting in the valve opening direction on the movable core 5 based on the differential pressure ΔP increases the biasing force f of the spring 6. When the valve member 10 becomes smaller than this, the valve member 10 slides toward the fixed core by the biasing force of the spring R, and is held at or near the position where the valve seat 9 is closed.

In this way, even if the valve member 10 moves to the position where the valve seat 9 is opened or closed, the differential pressure AP does not drop extremely rapidly, so the movable iron core 5 slowly approaches the fixed iron core 4. , it does not impact the fixed iron core 4.

When the excitation coil I and 2 are energized when the valve member lO is at or near the position where the valve seat 9 is closed, the attractive force of the fixed iron core 4 acts on the movable iron core 5, so that the valve member 1
0 is maintained to ensure that the valve seat 9 is closed. Therefore, even if the fluid pressure in the output flow path 8 decreases or disappears in this state, the valve member 10 maintains the valve seat 9 in the closed state.

When energizing the excitation coil 2, the fixed iron core 4 is in contact with or close to the movable iron core 5.
Therefore, the stroke of the movable core 5 is almost equal to zero, and even if a small electromagnetic operation unit is used, the attraction force of the fixed core 4 by the excitation coil 2 is very large (and therefore the valve is in the open state). Compared to a normal solenoid valve that attracts the valve member,
The electromagnetic operation section can be extremely miniaturized.

When the fluid pressure in the output flow path 8 is reduced and the current supply to the valve member 2 is cut off, the valve member 10 opens the valve seat 9 due to the fluid pressure in the input flow path 7, and the input flow path 7 also opens in the output flow path. 8 is supplied with fluid.

FIG. 3 shows an example in which the solenoid valve of the present invention is used as a pilot valve. In this pilot-type solenoid valve, a main valve 20 has a spool 22 slidably inserted into a hole bored in the axial direction of a valve body 21, and a large-diameter spool 22 at one end of the hole. A piston 23 inserted into the spool 22 is provided to be slidable together with the spool 22, and a return spring 2 is provided in a return chamber 24 at the other end of the spool 22 to urge the spool 22 toward the piston 23.
5 is provided. Further, the large diameter portion of the hole is closed by a mounting plate 26 fixed to the valve body 21, and a pressure acting chamber 27 is formed between it and the piston 23.

Furthermore, an input port S, an output port A, and a discharge boat R are opened in the valve body 21, and when the spool 22 is returned by the urging force of the return spring 25, the input port S and the output port A are communicated with each other. When the discharge boat R is closed and the spool 22 is driven by fluid pressure acting on the pressure chamber 27, which will be described later, the input port S is closed and the output port A and the discharge port R are communicated.

On the mounting plate 2i, solenoid valves IA and IB, which have the same configuration as the solenoid valve l shown in FIG. 1 described above, are attached as pilot valves. It is connected to the input port S by a pyrotechnical passage 28 formed in the plate 26 and the valve body 21, and is connected to the solenoid valve IA.
Is the output port 8a of the solenoid valve IB the input port? b, the pressure action chamber 2 is connected by a passage formed in the mounting plate 2B.
It is connected to 7. Also, the output capo of solenoid valve IB) 8b
is open to the atmosphere through a pilot exhaust passage 30 formed in the mounting plate 26 and the valve body 21.

Note that the main valve 20 may have the input port S communicate with the return chamber 24 through a passage 31, as shown by the chain line in FIG. 3, so that the supply fluid pressure is applied to the return chamber 24.

The electromagnetic valves IA and IB have the same configuration as the electromagnetic valve 1 shown in FIG. 1, so the same reference numerals in FIG.

To explain the operation of the pyrotechnic solenoid valve shown in FIG. and 5b are adsorbed, and fluid pressure is supplied to the pressure action chamber 27 to drive the spool valve 22 against the biasing force of the return spring 25.

Therefore, the valve members 10a and 10b hold the valve seats 9a and 9b in a closed state, and the pressure fluid supplied to the input flow path 7a through the input port S of the main valve 20 and the pilot supply path 29, and the pressure The flow of any pressure fluid supplied into the working chamber 27 is blocked. Also,
Since the subwoofer 22 is driven by the fluid pressure supplied to the pressure action chamber 27 against the biasing force of the return spring 25, the inlet port S of the main valve 22 is closed. Output port A and discharge port (R) are in communication.

In this state, the power supply to the coil 2b of the solenoid valve IH is cut off to eliminate the attractive force of the fixed iron core 4b.

Due to the fluid pressure in the pressure chamber 27 acting on the movable core 5b, the valve member 10b opens the valve seat 9b against the biasing force of the spring 6b. Therefore, the pressure fluid in the pressure action chamber 27 is released to the atmosphere through the valve seat 9b and the pilot exhaust path 30, and the spool 22 is returned by the urging force of the return spring 25, so that the input port S of the main valve 20 and the output Port A is communicated, and discharge boat R is blocked.

When the main valve 20 is switched, the solenoid valve IB
Since the pressure difference between the pressure fluid in the input flow path 7b and the output flow path 8b is very small, the movable core 5b is pressed toward the fixed core 4b by the biasing force of the spring 6b, and the valve member 10
b is held in a position that closes the valve seat 9b. Therefore, when the coil 2b of the solenoid valve IB is energized in this state, both iron cores are attracted by a very large attraction force, and the solenoid valve IB is held in the closed state.

Subsequently, when the power to the coil 2a of the solenoid valve IA is cut off, the attractive force of the fixed core 4a disappears, and the fluid pressure of the input flow path 7a acting on the movable core 5a causes the valve member 10a to absorb the biasing force of the spring 6a. The valve 9a is opened against the pressure, and the pressure fluid flows into the pressure action chamber 27. In this case, the fixed iron core 4b of the solenoid valve IB attracts the movable iron core 5b and maintains the closed state of the valve seat 9b, so that the pressure fluid flowing into the pressure action chamber 27 It is not released into the atmosphere through the air.

When the fluid pressure in the pressure action chamber 27 increases due to the inflow of pressure fluid, the spool 22 is moved by this fluid pressure, and the spool 22 returns to the state shown in FIG.

Further, when the fluid pressure in the pressure action chamber 27 increases and approaches the supply fluid pressure, the differential pressure between the input flow path 7a side and the output flow path 8a side acting on the movable iron core 5a becomes smaller, so that the spring 6a is attached. The force causes the valve member 10a to slide toward the fixed core 4a and move to a position where the valve seat 9a is closed. Therefore, when the coil 2a of the magnetic valve IA is energized.

Since the fixed core 4a attracts the nearby movable core 5a, the valve member 10a maintains the closed state of the valve seat 8a and returns to its original state.

'Coils 2a of solenoid valves IA and IB in the above-described operation.

2b, the movable cores 5a and 5b are the fixed core 4a.
, 4b, so even a small electromagnetic operating section can exert a large attraction force.

In addition, since the movable cores 5a, 5b do not impact the fixed cores 4a, 4b, the cores 4a, 4b and 5a,
5b can be prevented from being worn out.

Note that the stop position of the main valve can also be arbitrarily adjusted by independently controlling the timing of energization of the coils 2a and 2b.

[Effects of the Invention] In the present invention, the differential pressure between the input boat side and the output port side acting on the movable iron core is reduced, and the valve member is held in the position where the valve seat opens and closes by the biasing force of the spring. In this state, the movable core is adsorbed to the fixed core, so the adsorption force between the five cores is small enough to attract the adjacent movable core and keep the valve seat closed by the valve member. Therefore, not only can the hair operating section be downsized and the solenoid valve be downsized, but also the power consumption can be reduced.

In addition, the suction force of the fixed core only holds the movable core in close proximity and does not cause the fixed core and the movable core to come into contact with each other, so there is no wear on the core due to collision between the two cores.
The life of the solenoid valve can be extended.

[Brief explanation of drawings]

FIG. 1 is a longitudinal sectional front view of an embodiment of the present invention, FIG. 2 is a diagram showing the relationship between the differential pressure acting on the movable core of the solenoid valve of the present invention and the stroke of the valve member, and FIG. FIG. 2 is a longitudinal sectional front view showing an example of the use of the electromagnetic valve of the present invention. 1, IA, IB -- Solenoid valve, 2.2a, 2be
I: Iil. 4.4a, 4b a* Fixed core, 5.5a, 5b...Movable core. 13.13a, 13b II Life Spring 7.7a,
7b...Input flow path, 8.8a, 8b...Output flow path, 9a, 91) e *Valve seat, 10. lOa, 10
o--Valve member. Patent applicant: Sintered Metal Industry Co., Ltd. Figure 1 1'

Claims (1)

[Claims] 1. A fixed iron core is fixed in the center hole of the coil, and a movable iron core is slidably inserted, and a valve member provided at one end of the movable iron core closes the valve seat by attracting both iron cores. In the electromagnetic valve configured to shut off the flow of fluid, a spring is provided on the movable core to bias it toward the fixed core, and the biasing force of the spring is supplied from the input port through the valve seat. When the pressure of the primary fluid is sufficiently greater than the pressure of the secondary fluid, the movable iron core is pressed in the valve seat by the pressure of the primary fluid acting on it and opens the valve. 1. A solenoid valve characterized in that the movable iron core is set to such an extent that the movable iron core is held in the valve closed position by the biasing force when the fluid pressure difference becomes small.