JPS6021590Y2 - Pilot operated directional valve - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a pilot operated directional valve used to form a remotely operated pressure fluid circuit.

Conventionally, this type of pilot-operated directional valve
There is one shown in Fig. 1 (Utility Model Application No. 19125/1983).

This pilot-operated directional control valve A' has an operating portion 4' connected to a spool-type directional control valve 6'.

This operating section 4' includes a cylinder B' connected to the spool 5' of the spool-type directional control valve 6', and a solenoid valve C' that supplies and discharges pilot pressure fluid to and from the pressure chambers B1' and B2' of this cylinder B'. and more.

This solenoid valve C' has a neutral position CI' and a switching position C2'C.
3' and electromagnets C4' and C5'.

This pilot-operated directional control valve A' is switched to the switching position C2 when an operation command is given to the electromagnet C4' of the solenoid valve C'.
', the pressure chamber B1' of the cylinder B' is connected to the tank T' via the discharge passage 37', and the pressure chamber B2'
is connected to the pilot pressure fluid source PP via the supply channel 38', so that the cylinder B' switches the spool-type directional valve 6' into the left switching position 5a'.

Furthermore, when an operation command is given to the electromagnet C5', pilot pressure fluid is supplied to the pressure chamber B1' of the cylinder B', and the fluid in the pressure chamber B2' is discharged to the tank T'.
The spool-type directional valve 6' switches to the right switching position 6b'.

The pilot-operated directional control valve A' having the above structure has the following problems because its operating portion 4' is provided with a solenoid valve that is a 4-point 3-position directional control valve.

In other words, the 4-point, 3-position directional control valve of the operating section only switches between 2 of the 4 ports when switching from one position to another.
It is necessary to switch ports one by one at the same time.

(For example, in FIG. 1, the solenoid valve C' is at the neutral position CI
When switching from ' to switching position C3', pressure chamber B1' of cylinder B' is connected to pilot pressure fluid source PP, and at the same time pressure chamber B2' is connected to tank T'.

Therefore, the connection between the port to which the pilot pressure fluid source PP is connected and the port to which the pressure chamber Bl' is connected, and the connection between the port to which the tank T' is connected and the port to which the pressure chamber B2' is connected are made simultaneously. .

) Therefore, the configuration is a type of switching valve in which the valve slides within the valve body (for example, the most common type of valve is a spool type directional switching valve).

Therefore, this spool type directional control valve will be described below.

) is a device in which a valve (spool) is slidably inserted into a valve body, and the connection relationship of ports is switched by operating this spool.

In this way, it is necessary to provide a gap between the valve body and the spool in order to move the spool.

Therefore, when the spool of this 4-point, 3-position type directional control valve is stopped at the neutral position or any switching position, there is a gap between the port connected to the supply passage and the port connected to the discharge passage. is acted upon by the fluid pressure differential between the pilot pressure fluid source and the tank.

Therefore, this fluid pressure acts on the minute gap between the valve body and the spool.

This fluid pressure causes the spool to be pressed against one side of the valve body, resulting in a so-called hydraulic lock.

In addition, when the pressure fluid passes through the small gap between the valve body and the spool, the spool tends to stick to the valve body due to dirt in the fluid being accumulated in the small gap, so the solenoid valve is operated by the pilot. This causes malfunction of the mold directional control valve.

The technical problem of the present invention is to prevent malfunction of a pilot-operated directional control valve by using a solenoid valve that does not require a minute clearance in the operation part of the pilot-operated directional control valve.

The technical means of the present invention for solving the above technical problem is to provide a spool-type directional control valve with an operating section, and connect this operating section to a spool of the spool-type directional control valve with a cylinder and a cylinder that connects the operating section to the spool of the spool-type directional control valve. In the pilot-operated directional control valve configured to include a solenoid valve between the pressure chamber and a pilot pressure fluid supply passage and a discharge passage, the operating section opens and closes between the supply passage and the pressure chamber. An electromagnet is driven to drive a poppet valve body of a poppet valve, an opening of the discharge passage is provided between the poppet valve and the pressure chamber, a valve body is disposed between this opening and the poppet valve, and the valve The body has a restriction that communicates the poppet valve with the pressure chamber, and receives the pressing force from the spring from the pressure chamber side, and the pressure difference that occurs when the pressure fluid passes through the restriction of the valve body is approximately equal to the pressing force of the spring. The lower end of the valve body narrows the opening so as to maintain the opening.

In the present invention having the above technical means, if the driving force of the electromagnet does not act on the poppet valve of the operation part, the poppet valve body contacts the valve seat and closes the gap between the supply passage and the pressure chamber. When the poppet valve element receives a driving force from the electromagnet, the poppet valve body moves far away from the valve seat.

Therefore, since the poppet valve does not form a minute gap during operation and non-operation, it does not cause hydraulic lock due to pressure fluid and no accumulation of dust.

In addition, the valve body installed between the poppet valve and the pressure chamber is
When the cylinder holds the spool of the spool firing switching valve in one switching position, only the pressure difference corresponding to the spring force that presses the valve body before and after the valve body throttles acts, so a hydraulic lock is applied. Also, dust accumulation does not occur and sticking caused by these is prevented.

Therefore, the present invention is intended to prevent malfunctions caused by the solenoid valve of a pilot-operated directional valve.

The present invention having the above configuration has the following unique effects.

Another technique for solving the technical problems of the present invention is shown in FIG. 2 (Japanese Unexamined Patent Publication No. 57-103914).

Another technique shown in FIG. 2 is a spool type directional control valve 6.
An operating section 4" is connected to the cylinder B, which is connected to the spool 5", pressure chambers B1" and B2" of the cylinder B, and a pilot pressure fluid supply passage 3.
Poppet valves DI" and D2" driven by electromagnets C4" and C5" are provided between the pressure chamber 81" and the pressure chamber 81".
, 82'' and the discharge passage 37'', a fixed throttle B3'', B
4".

In this technology, when an excitation command is given to the solenoid valve C4'', the poppet valve D1'' opens and pilot pressure fluid flows into the pressure chamber B1'', and this pilot pressure fluid flows into the fixed throttle B1''.
3" into the discharge passage 37", the pressure chamber Bl
The fluid pressure generated by the fixed throttle 83'' acts on the fluid in the other pressure chamber B2'', and the fluid in the other pressure chamber B2'' acts on the fixed throttle 84''.
It flows out to the discharge passage 37'' through the cylinder B''.
moves the spool 5'' to the left to switch the spool type directional switching valve 6''.

According to the technique having the above configuration, since a poppet valve is used as the solenoid valve, it is possible to prevent the solenoid valve from sticking and malfunction of the pilot-operated directional valve.

However, in this technique, the pressure chambers B1" and B2" are connected to the discharge passage through fixed throttles B3" and 84", so the consumption of pilot pressure fluid increases. If the aperture areas of the apertures B3" and B4" are made smaller, the switching speed will be limited.

Therefore, in relation to the switching speed, the fixed aperture B3",
It is necessary to increase the opening area of B4''.

Therefore, during switching or when stopped at the switching position, pilot pressure fluid is discharged into the tank.

The present invention provides an opening for a discharge passage between the poppet valve and the pressure chamber, and has a restriction that communicates the poppet valve and the pressure chamber at a position where this opening is opened and closed, and a pressing force applied by a spring from the pressure chamber side. When the pilot valve is open, this valve body receives the pressing force of the spring and is in a position that connects the pressure chamber to the discharge passage, and when the pilot valve opens, pressure is discharged from the supply passage. When the pilot pressure fluid flows into the chamber, the opening is closed by the fluid pressure difference that occurs before and after the valve body is throttled.

When the cylinder stops at one operating position, the valve body narrows the opening so as to maintain the fluid pressure in the pressure chamber at a value lower than the fluid pressure in the supply passage by the pressing force of the spring.

Therefore, the switching speed is not limited by the flow of fluid from the pressure chamber to the discharge passage, but is limited only by the throttle of the valve body, and the pressing force of the spring that presses the valve body is limited by the pressure of the spring when the poppet valve is closed. The value can be set to a small value as long as the value is enough to push the opening to the position where the opening is opened.

Therefore, according to the present invention, it is possible to eliminate the release of pilot pressure fluid into the tank during switching and to make the release of pilot pressure fluid into the tank when stopping at the switching position to a minute flow rate. consumption can be reduced.

Below, Fig. 3 shows an embodiment in which the present invention is applied to a pilot-operated directional valve that can be operated both remotely and manually.
Let's talk about Figure 4.

The pilot-operated directional valve A includes a pressure fluid source 1 and an actuator (not shown).

) and a tank T, and a spool 5 which is slidably fitted into an inner hole 3 provided in the valve body 2 and whose one end is connected to the operating lever 1. Directional switching valve 6 and valve body 2 of this spool-type directional switching valve 6
The spool 5 is fixed to the end 7 of the spool 5, and is connected to the other end of the spool 5 to operate the spool 5.

Although the spool-type directional control valve 6 is not shown, it is one of a plurality of directional control valves that are arranged in series to form a parallel circuit, for example.

The inner hole 3 provided in the valve body 2 of the spool-type directional control valve 6 and into which the spool 5 is slidably inserted is connected to the pressure fluid source 1.
Annular i9a, 9b to which the discharge side piping 8a connects, grooves 11a, llb to which the load passages lea, 10b to the actuator connect, grooves 13a, 13b to which the discharge passage 12 to the tank T connects, and the piping. A passage 16a that is connected to a pipe 8b branching from 8a and connected via a check valve 15 to a supply passage 14 that is closed by the final stage spool-type directional control valve when a plurality of spool-type directional control valves 6 are installed in series. ,
16b is connected to the grooves 17a and 17b, and when a plurality of spool-type directional control valves 6 are installed in series, the last stage spool-type directional control valve is connected to the discharge passage 12 through the annular groove of the subsequent spool-type directional control valve. It has an annular groove 18.

A spool 5 that is slidably fitted into this inner hole 3 is a third
In the neutral position shown in the figure, grooves 13a and 11a and R1
Large diameter portion 20a, 20 that closes between 3b and llb
b, groove 17a and annular groove 9a, and groove 17b and annular groove 9
The large diameter portions 21a and 21b that close the space between the grooves 1 and 1
8, a large diameter portion 22 located between the large diameter portions 20a and 21a, and small diameter portions 23a and 23b provided between the large diameter portions 20b and 21b, respectively, and the large diameter portion 22 and the large diameter portion 21a.
The small diameter portion 24a provided between each of the small diameter portions 24a and t2ib.

24b, the left end 25 of which is connected to the operating lever 1, and the right end 26 of which is connected to the piston 35 of the operating portion 4.

This spool-type directional control valve 6 is configured so that when the spool 5 is in the neutral position shown in FIG.
The discharge pressure fluid flows out into the tank T, and the spool 5 moves rightward from the neutral position in FIG.
, 22 close the annular groove 18 and the annular grooves 9a, 9b, respectively, and connect the load passages 10a, 10b to the passage 16a and the discharge passage 12 by their small diameter portions 23a, 23b.

Further, the spool 5 moves leftward from the neutral position in FIG.
.

9b, and load passages 10a,
10b, its small diameter portions 23a, 23b connect to the discharge passage 12 and the passage 16b.

Note that the passage 27 provided in the main body 2 is connected to a pilot pressure fluid source (not shown, but a part of the pressure fluid discharged from the pressure fluid source 1 is diverted, or a pilot pressure fluid source is separately provided as shown in FIG. 1). It may be provided.

) is connected to the discharge side of the pilot pipe 28, which is connected to the operating section 4, which will be described later, via a passage 29.When a plurality of spool-type directional control valves are installed in series, the final stage It will be closed.

The operating portion 4 includes an inner hole 36 into which a piston 35 connected to the right end 26 of the spool 5 of the spool type directional control valve 6 is slidably fitted, a supply passage 37 connected to the passage 27, and a passage of the valve body 2. A discharge passage 38 is connected to the discharge passage 12 via a discharge passage 30, and one end thereof is open to the inner hole 36.
Inner holes 46a and 46b where 8 is open, and this inner hole 46a
, 46b, and has a cylinder 50 provided with an inner hole 47at47b to which the supply passage 37 is connected.

The right end of the inner hole 36 of this cylinder 50 is connected to the piston 3.
It is closed with a lid 44 through which a rod 43 connected to the spool 5 and having the same diameter as the large diameter portion 20b of the spool 5 and to which the pressing force of the spring 45 of the neutral position return device 42 is passed.
An inner hole 36 provided in the end 7 of the valve body 2 and a recess 31 having the same diameter are connected by a ring 32 so as to be aligned with the axis of the spool 5.

Note that 39a and 39b are pressure chambers, and these pressure chambers 39a,
39b are inner holes 46a and 47a.

Supply passage 3 via electromagnetic valves 40a, 40b provided in 46b, 47b and actuated by electromagnets 41a, 41b.
7 or the discharge passage 38.

The electromagnets 41a, 41b have coils 51a, 51b, fixed iron cores 52a, 52b, and a poppet valve body 53a+ at the tip.
It has movable iron cores 54a and 54b having 53b,
These movable iron cores 54a, 54b are connected to the inner hole 47ay4.
7b, and to which the sleeves 55a, 55b, which fit into the inner holes 46a, 46b, are screwed together.
a, 56 through b.

In addition, these movable iron cores 54a, 54b and fixed iron cores 52a, 5
2b, springs 70a and 70b are provided and communicated with the supply passage 37 via grooves 69a and 69b.

The solenoid valve 40at40b is connected to the sleeves 55a and 55b.
The supply passage 3 is formed through the through holes 57a and 57b.
Upper inner hole 58a connected to 7.

A poppet valve 60a formed by valve seats 59a and 59b formed at the lower part of 58b and the poppet valve bodies 53a and 53b.
, 60b and the lower inner hole 61a of the sleeves 55a, 55b.
, 61b so as to be slidably inserted into the lower inner holes 61a, 61b.
Spring 63a held by rings 62a, 62b provided below.

A valve body 65aw65b that is always pressed upward by a valve 63b and has throttles 64a and 64b, and these valve bodies 65a and 6
Openings 67a, 6 which connect the lower ends 66a, 66b of 5b with the discharge passage 38 and open into the lower inner holes 61a, 61b.
7b, and valve portions 68a and 68b.

These solenoid valve parts 40a, 40b are connected to the electromagnets 41a, 4
The poppet valve bodies 53a, 53b are separated from the valve seats 59a, 59b by the excitation force of the valve body 1b, and the pilot pressure fluid is directed from the supply passage 37 toward the pressure chambers 39a, 39b through the throttles 64a of the valve bodies 65a, 65b. , 64b, the lower ends 66a, 66b of the valve bodies 65a, 65b
is for closing the through holes 67a and 67b.

Next, the operation of this embodiment will be described.

In FIG. 3, when no operation command is given to the electromagnets 41a * 41b (when no excitation current is supplied), the movable iron cores 54a and 54b are operated by the pressing force of the springs 70a and 70b and the pilot from the supply passage 37. Pressure fluid flows into the movable iron core 5 through the grooves 69a and 69b of the movable iron cores 54a and 54b.
4a, 54b, so the movable iron core 54a,
The poppet valve bodies 53a, 53b at the tips of 54b abut against the valve seats 59a, 59b of the sleeves 55a, 55b.

(Both poppet valves 60a and 60b are closed.

) Therefore, the valve bodies 65a, 65b are connected to the springs 63a, 63b.
The lower ends 66a, 66b are pressed by the sleeve 55.
a, 55b openings 67at67b and pressure chambers 39a, 3
It is located at the position where 9b is connected.

Therefore, the pressure chambers 39 at 39 b are connected to the lower inner holes 6ta and 61b of the sleeves 55a and 55b, and the opening 67.
a, 67b to discharge passage 38, passage 30.513b
It is connected to the discharge passage 12 of the valve body 2 through.

In this manner, the piston 35 is freely movable, and when no operating force is applied to the operating lever 1, the spring 45 of the neutral position return device 42 is applied to the spool 5 of the spool-type directional control valve 6. A pressing force acts via the rod 43 and piston 35 to hold it in the neutral position shown in FIG.

When the spool 5 of the spool-type directional control valve 6 is held in the neutral position, the pressure fluid discharged from the pressure fluid source 1 is
It flows out from the discharge passage 12 to the tank T via the pipe 8a, the annular grooves 9a and 9b of the inner hole 3 of the valve body 2, and the annular groove 18.

At this time, the load path 10a to the actuator = 1
0b is closed by the large diameter portion 20at21a of the spool 5 and the large diameter portions 20b and 21b, respectively.

Next, an operation command is given to the electromagnet 41a (excitation current is supplied).

), the movable iron core 54a moves upward against the pressing force of the spring 70a, and the poppet valve body 53a is separated from the valve seat 59a.

(Poppet valve 60a opens.

) When the poppet valve 60a opens in this way, the pilot pressure fluid being supplied to the passage 27 via the pilot pipe line 28 flows through the passage 29, the supply passage 37, the through hole 57a1 of the sleeve 55a, the valve seat 59a1, and the valve body 65a. It attempts to flow into the pressure chamber 39a through the lower inner hole 61a of the throttle 64a1 and also flows out into the discharge passage 38.

The flow of this pilot pressure fluid creates a pressure difference before and after the throttle 64a of the valve body 65a, and the valve body 65a is moved by the spring 63a.
The lower end 66 of the valve body 65a is moved downward against the pressing force of the valve body 65a.
a closes the opening 67a.

Therefore, the pilot pressure fluid from the supply passage 37 passes through the valve seat 59a and the throttle 64a of the valve body 65a to the pressure chamber 39a.
flows into.

In this way, the pilot pressure fluid flows into the pressure chamber 39a, and the pressure of the fluid against the piston 35 reaches a value that overcomes the pressure of the spring 45 of the neutral position return device 42 and the sliding resistance of the spool 5. Then, the piston 35 moves to the right together with the spool 5.

When the spool 5 finishes moving rightward, its large diameter portions 21a and 22 close between the annular grooves 18 and 9a and 9b, and the small diameter portion 23a closes the space between the load passage 10a and the passage 1.
6a, and the small diameter portion 23b connects the load passage 10b and the discharge passage 12.

When the spool 5 moves in this way, the pipe 8a is closed, so that the pressure fluid discharged from the pressure fluid source 1 is transferred to the pipe 8b.
.

Push open the check valve 15 through the supply passage 14, and open the passage 16.
Fluid flows into the actuator from the load passage 10a through the a1 inner hole 3 and flows out from the load passage 10b inner hole 3, groove 13b1 and discharge passage 12 to the tank T, so that the actuator begins to operate.

When the piston 35 of the operating section 4 operates the spool 5 of the spool type directional control valve 6 as described above, the piston 35 of the operating section 4 advances to the rightmost position and stops its displacement, so that the pilot pipe 28 , passages 27, 29, supply passage 3
7. Since the flow of the pilot pressure fluid from the poppet valve 60a1 through the throttle 64a of the valve body 65a is stopped, the pilot fluid pressure before and after the throttle 64a of the valve body 65a becomes the same pressure, so that the valve body 65a The valve body 68a opens due to the pressing force of the spring 63a, and the lower inner hole 6 of the spool 55a opens.
A portion of the pilot pressure fluid in 1a is transferred to the discharge passage 38,
Discharge passage 1 of directional control valve 6 via passage 30 and groove 13b
Discharge to 2.

Therefore, the pilot pressure fluid flows again into the throttle 64a of the valve body 65a, and the valve body 65a is positioned in a state where the fluid pressure difference before and after the throttle 64a is balanced with the pressing force of the spring 63a, and the fluid in the pressure chamber 39a is The pressure is also controlled to a value depending on the balanced state of this valve 65a.

While the operation command is given to the electromagnet 41a, the fluid pressure in the pressure chamber 39a is maintained at a constant value by the above-described action of the valve portion 68a, so that the spool 5 of the directional control valve 6
is also maintained in the state described above.

Next, when the operation command to the electromagnet 41a is stopped, the suction force of the movable iron core 54a is released, so that the movable iron core 54a receives the pressing force of the spring 70a and its poppet valve body 53a is seated on the valve seat 59a. The poppet valve 60a closes.

Therefore, since the valve body 65a of the valve portion 68a also moves upward due to the pressing force of the spring 63a, the pressure chamber 39a
A is connected to the discharge passage 12 through the lower inner hole 61a, the through hole 67a1, the discharge passage 38, the passage 30, and the groove 13a.

At this time, since no operation command is applied to the electromagnet 41b, the pressure chamber 39b is also connected to the discharge passage 12 together with the pressure chamber 39a via the lower inner hole 61b1 of the sleeve 55b and the discharge passage 38.

In this way, since both the pressure chambers 39a and 39b of the operating section 4 are connected to the discharge passage 12, the pressing force of the spring 45 of the neutral position return device 42 moves the spool 5 through the rod 43 and the piston 35. Return to the neutral position shown in Figure 3.

The case where an operation command is given to the electromagnet 41a has been described above. However, when an operation command is given to the electromagnet 41b, the movable iron core 54b moves upward, the poppet valve 60b opens, and the pilot pressure fluid flows into the supply passage 37. , the throttle 64 of the valve body 65b
Flows into the pressure chamber 39b via b and moves the spool 5 of the directional control valve 6 to the left.

When the spool 5 is switched, the pressure fluid discharged from the pressure fluid source 1 is transferred to the pipe 8b.

The fluid in the actuator flows into the actuator via the check valve 15, the passage 16b1 and the load passage 10b, and the fluid in the actuator flows out from the load passage 10a through the discharge passage 12 to the tank T, so that the actuator is driven in the opposite direction to that described above. .

Further, the spool 5 moves to the left, the piston 35 of the operating part 4 also reaches the left end, and the valve part 68b moves to the above-mentioned valve part 68.
It operates in the same manner as in step a to maintain the pilot fluid pressure in the pressure chamber 39b at a constant value and to maintain the switching position of the spool 5.

In this way, by giving an operation command to either of the electromagnets 41a, 41b, the spool 5 of the directional control valve 6
can be operated from the neutral position to the left/right switching position.

When no operation command is given to either of the electromagnets 41a, 41b, the pressure chambers 39a, 39b of the operating section 4 communicate with the tank T via the discharge passage 12 via the discharge passage 3B, passage 30, By operating the operating lever 1, the spool 5 of the spool-type directional control valve 6 can be manually operated.

In this case, as the spool 5 moves, only the low pressure fluid in the tank T is sucked into and discharged from the pressure chambers 39a and 39b of the operating section 4, and the pilot pressure fluid is
, 60b remains closed.

According to the above embodiment, when no operation command is given to the solenoid valve, or when the electromagnet is damaged, the valve body
Since the pressure chamber is connected to the tank, there is no resistance to the operation of the control lever due to the supply and discharge of fluid to the pressure chamber, and the operation can be performed in the same way as the operation of a normal directional control valve. have an effect.

[Brief explanation of the drawing]

FIG. 1 is a circuit diagram of a conventional pilot-operated directional control valve. FIG. 2 is a sectional view of another conventional example. FIG. 3 is a sectional view of an embodiment of the present invention. FIG. 3 is an enlarged cross-sectional view of the operating section shown in the figure. 4...Operation unit, 5...Spool, 6.
Curved/spool type directional control valve, 37... Supply passage, 38... Curved discharge passage, 39 a, 39 b...
...Pressure chamber, 40...Open type magnetic valve, 41a, 41b...Open type magnet, 5o, curve, cylinder, 60 a, 60 b
=Poppet valve, 63a. 63b... Spring, 64ay 64b...
... Throttle, 65at65b... Valve body, 67a,
67b...Opening.

Claims (1)

[Scope of utility model registration request] An operating section is connected to the spool-type directional control valve, and the operating section is connected between a cylinder connected to the spool of the spool-type directional control valve, a pressure chamber of this cylinder, and a pilot pressure fluid supply passage and a discharge passage. In a pilot-operated directional control valve configured to include a solenoid valve, the operating section includes:
A poppet valve element of a poppet valve that opens and closes between the supply passage and the pressure chamber is driven by an electromagnet, an opening of the discharge passage is provided between the poppet valve and the pressure chamber, and the opening and the poppet A valve body is arranged between the poppet valve and the pressure chamber, and this valve body has a restriction that communicates the poppet valve with the pressure chamber, receives a pressing force from a spring from the pressure chamber side, and when the pressure fluid passes through the restriction of the valve body. The pilot-operated directional control valve is configured such that the lower end of the valve body narrows the opening so that the resulting pressure difference is maintained at a value approximately equal to the pressing force of the spring.