JPH0640322Y2 - Liquid control device - Google Patents

Description

[Detailed Description of the Invention] [Industrial field of application] The present invention is directed to a poppet operated by a pilot valve having a valve seat interposed between a supply flow path connected to a hydraulic pressure source and a load flow path connected to an actuator. The present invention relates to a liquid control device which is opened and closed by a valve.

[Prior art]

 A conventional example will be described with reference to FIG.

Reference numeral 4 denotes a main body, which is a supply flow path P connected to a hydraulic pressure source in the main body 4, a load flow path A connected to the rod side working chamber 2 of the cylinder 1 and a load flow path B connected to the head side working chamber 3 of the cylinder 1. A poppet main valve 5 for controlling communication between the supply flow path P and one of the load flow paths A, and a drain flow path R connected to the storage tank T and a drain discharge path DR connecting the drain fluid to the storage tank T. Supply channel P
Main valve 6 for controlling the communication between the load flow path B and the other load flow path B
A poppet main valve 7 for controlling communication between the discharge flow path R and one load flow path A, and a poppet main valve 8 for controlling communication between the discharge flow path R and the other load flow path B. Main valves 5, 6,
Nos. 7 and 8 have the same basic configuration, and are Taber-shaped valve portions 5b, 6b and 7 which are respectively seated on the valve seats 5a, 6a, 7a and 8a.
b, 8b are provided so as to be movable, and each main valve 5, 6, 7, 8
The second working chambers 5d, 6d, 7d, 8d formed on the back of the valve and the springs 5e, 6e, 7e, 8e bias the main valves 5, 6, 7, 8 in the closing direction, and Each main valve 5, 6, 7, 8 is biased in the opening direction by the hydraulic pressure of the first working chamber 5c, 6c, 7c, 8c. And
In the discharge passages 5f, 6f, 7f, 8f connecting the second working chambers 5d, 6d, 7d, 8d to the drain discharge passage DR, the second pilot valves 13, 14,
The on-off switching valves 13a, 14a, 15a, 16a of 15 and 16 are interposed, and the second
The liquids in the working chambers 5d, 6d, 7d, 8d introduce the liquids in the load channels A, B via the first throttles 5g, 6g, 7g, 8g, and the first working chamber 5
Open / close switching valves 13a, 14 by the pressure of the liquid introduced to c, 6c, 7c, 8c
Second pilot valve 13, 14, 15, 1 for operating a, 15a, 16a
The operation switching valves 13b, 14b, 15b, 16b of 6 are switched. 9, 10, 11 and 12 are diaphragms 9a, 10a, 11a,
12a and a first pilot valve having current control type relief valves 9b, 10b, 11b, 12b for supplying pressure fluid to the first working chambers 5c, 6c, 7c, 8c of the poppet main valves 5, 6, 7, 8 I am trying to guide you.

In the state of FIG. 4, the first pilot valves 9, 10, 11, 12 are in the non-energized state, the first working chambers 5c, 6c, 7c, 8c are in the atmospheric pressure state, and the operation switching valves 13b, 14b, The open / close switching valves 13a, 14a, 15a, 16a cut off the discharge paths 5f, 6f, 7f, 8f connected to the drain discharge path DR in the normal position, and the poppet main valves 5, 6, 7, 8 are respectively provided with 15b, 16b. The valve seats 5a, 6a, 7a, 8a are closed, and the load passages A and B are cut off from the supply passage P and the discharge passage R.
Now, when the relief valves 9b and 12b of the first pilot valves 9 and 12 are energized with a predetermined value of current from the state shown in FIG. 4, the liquid that presses the valve seats 5a and 8a to the poppet main valves 5 and 8 in the opening direction. At the same time when the pressure is introduced into the first working chambers 5c and 8c, the operation switching valves 13b and 16b of the second pilot valves 13 and 16 are switched to open the open / close switching valves 13a and 16a, and the second working chamber 5d, In order to discharge the liquid in 8d to the drain discharge path DR, the action of the first throttles 5g and 8g causes the second
The hydraulic pressure in the working chambers 5d and 8d becomes about atmospheric pressure, and the first working chamber 5d
The poppet main valves 5 and 8 move in the opening direction to open the valve seats 5a and 8a to a position where the hydraulic pressure of the hydraulic pressures c and 8c and the spring force of the springs 5e and 8e are balanced, and the head side of the cylinder 1 A flow rate corresponding to the position of the poppet main valve 8 is discharged from the working chamber 3 to the supply flow channel P and the discharge flow channel R, and the liquid flows from the supply flow channel P to the load flow channel A to the rod side working chamber 2 of the cylinder 1. Is introduced to move the piston of the cylinder 1 downward from the state shown in the figure. Similarly, when an electric current of a predetermined value is applied to the first pilot valves 10 and 11 from the state of FIG. 4, the hydraulic pressure corresponding to the electric current value is applied to the first working chamber.
6c, 7c, the second pilot valves 14 and 16 are operated, the poppet main valves 6 and 7 move in the opening direction, and the valve seats 6a and 7a
Is opened and the piston of the cylinder 1 is moved upward.

[Problems to be solved by the invention]

In this configuration, for example, when the cylinder 1 energized to the first pilot valves 10 and 11 is moved upward to move the piston upward, another actuator (not shown) whose operating pressure is smaller than that of the cylinder 1 due to the liquid from the hydraulic pressure source is used. When actuated, the piston of the cylinder 1 descends. Therefore, in order to prevent such a situation, a pilot operated check valve is installed in the load passage B.
There is a problem that it becomes necessary to install 24 and the liquid control device becomes large.

The present invention intends to solve the above problems by allowing the poppet main valve between the supply passage and the load passage to be closed when the load passage becomes higher in pressure than the supply passage. Is.

[Means for solving problems]

For this reason, the present invention has a valve seat interposed between a supply flow path connected to a hydraulic pressure source and a load flow path connected to an actuator, and a valve portion seated so as to close the valve seat. A poppet main valve that opens and closes, a spring that presses the poppet main valve in a direction that closes the valve seat, and a first working chamber that applies a pressing force to the poppet main valve in the direction that opens the valve seat by the internal hydraulic pressure,
The first pilot valve, which applies hydraulic pressure to the first working chamber to open the poppet main valve, is connected to the load flow path through a throttle, and when the communication to the low pressure side is cut off, the internal hydraulic pressure causes the poppet to flow. In the second working chamber that presses the main valve to close the valve seat and eliminates the pressing due to this hydraulic pressure when communication is made to the low pressure side, and the discharge passage that connects the second working chamber to the low pressure side. A second pilot valve that is provided to open the second working chamber to communicate with the low pressure side when the poppet main valve is opened, and a second pilot valve that is provided in the discharge passage and has a second pressure when the load flow passage becomes higher in pressure than the supply flow passage. The valve mechanism is configured to be closed so as to cut off the communication between the working chamber and the low pressure side.

[Action]

In the configuration of the present invention, when the pressure of the load flow passage becomes larger than the pressure of the supply flow passage with the poppet main valve having the valve seat open, the valve mechanism is closed to prevent outflow to the discharge passage. The hydraulic pressure in the second working chamber rises to the pressure in the load passage,
As a result, even if hydraulic pressure is applied to the first working chamber, the spring of the poppet main valve and the poppet main valve that is pressed by the action of the hydraulic pressure of the second working chamber that has increased in pressure move toward the direction of closing the valve seat. The valve seat closes the valve seat, and the load passage and the supply passage are shut off from each other. Since this valve mechanism is provided in the discharge passage from the second working chamber to the low pressure side, the valve mechanism becomes small and the valve body does not become large.

〔Example〕

An embodiment of the present invention will be described below with reference to FIGS. 1 and 2.

Reference numeral 4 denotes a main body, a poppet main valve 5 for controlling communication between a supply flow path P connected to a hydraulic pressure source such as a hydraulic pump and one load flow path A, a supply flow path P and the other load flow path B. A poppet main valve 6 for controlling communication between the two, a poppet main valve 7 for controlling communication between the discharge flow path R connected to the storage tank T and one load flow path A,
It has a poppet main valve 8 for controlling the communication between the discharge flow path R and the other load flow path B, and a drain discharge path DR connected to the storage tank T, and operates the main valves 5, 6, 7, 8 respectively. First pilot valve 9, 10, 1 that functions as a controlling pilot valve
1, 12, second pilot valves 13, 14, 15, 16, a differential pressure pilot valve 17 for the second poppet main valve 6, and an opening / closing pilot valve 18 for the fourth poppet main valve 8. The main valves 5, 6, 7 and 8 have the same basic structure. As shown in FIG. 2 by taking the first poppet main valve 5 as an example, the same diameter is provided on both upper and lower sides of the large diameter hole 50a. The small diameter holes 50b and 50c are coaxially provided, and the stepped inner hole 50 is formed by forming the valve seat 5a in the lower step portion, and at the end of the large diameter hole on the side close to the valve seat 5a. It has a first annular groove 51a which is formed and communicates with the load flow path A, and a second annular groove 51b which is formed in the middle of the lower small diameter hole 50b and communicates with the supply flow path P. And
Large diameter portion 52 and valve seat 5a slidably inserted in large diameter hole 50a
It has a taper-shaped poppet valve portion 5b that sits on or detaches from the load passage A and the supply passage P to block communication, and has a large diameter hole 50a.
A first liquid chamber 53 that is in constant communication with the annular groove 51a is formed by the second throttle 5h on the side of the small diameter hole 50c so that the pressure of the load flow path A is balanced, and on the lower side of the poppet valve portion 5b. Below the connecting portion 55, a connecting portion 55 that is provided and extends into the small diameter hole 50b below and forms a second liquid chamber 54 that communicates with the small diameter hole 50b and through the valve seat 5a to the load flow path A is provided. Small diameter hole 50b provided below
A first working chamber 5c which is slidably inserted into the small diameter hole 50b and a pilot pressure is applied to the end of the small diameter hole 50b.
A spool portion 57 that forms a third liquid chamber 56 is integrally provided in the portion 51b, and is provided on the upper side of the poppet valve portion 5b and slidably inserted into an upper small diameter hole 50c. It has a spool portion 58 forming a second working chamber 5d which is always connected to the first annular groove 51a through the first throttle 5g and is selectively connected to the drain discharge passage DR by the second pilot valve 13. . Therefore, the intermediate portion of the spool portion 57 described above is passed through the communication passage 59 including an inner hole axially provided in the shaft center of the spool portion 57 and the coupling portion 50 and a radial hole provided in the coupling portion 50. An opening 59a communicating with the third liquid chamber 56 is formed, and the opening 59a, the inner wall of the small diameter hole 50b, and the second annular groove 51b cause the poppet main valve 5 to move upward, so that the poppet valve portion 5b and the valve seat 5a are separated from each other. The variable throttle portion G having a flow passage area which is always smaller than the flow passage area formed in the above. Each of the first pilot valves 9, 10, 11, 12 is connected to the supply flow path P via the pressure reducing valve 25, and the throttles 9a, 10a, 11a, 12a and the current control type of which the set pressure changes according to the energization value are used. Relief valves 9b, 10
b, 11b, 12b, each of which exerts a pressure that rises from the atmospheric pressure when not energized according to the energization value between the relief valves 9b, 10b, 11b, 12b and the throttles 9a, 10a, 11a, 12a. Chamber 5c, 6c, 7
The flow paths 19, 20, 21, and 22 are introduced into c and 8c. Each second pilot valve 13, 14, 15, 16 is a discharge passage that connects each second working chamber 5d, 6d, 7d, 8d to the drain discharge passage DR.
Normally closed switching valves 13a, 14a, 15 provided on 5f, 6f, 7f, 8f
Flow path from a, 16a and each first pilot valve 9, 10, 11, 12
Open / close switching valve 13a, 1 operated by hydraulic pressure guided by 19, 20, 21, 22
Operation switching valves 13b, 14b, 15b, 1 for opening 4a, 15a, 16a
It has 6b. The open / close pilot valve 18 is provided with a current control type relief valve 18a and a normally closed electromagnetically operated open / close valve 18b in a discharge passage 8K connecting the first liquid chamber 83 of the poppet main valve 8 to a drain discharge passage DR. 2 throttling 8h Normally closed on-off valve provided in the discharge passage 8m connecting the second working chamber 8d to the drain discharge passage DR with a differential pressure across the drain
I am trying to open 18c. The differential pressure pilot valve 17 is provided with a normally closed on-off valve 17a which is urged to a closed state by a spring 17b in the discharge passage 6f, and the hydraulic pressure of the supply flow passage P from the flow passage 23 and the first liquid chamber 63 of the poppet main valve 6 are provided. The differential pressure of the hydraulic pressure in the load flow path P derived from the on-off valve 17a
The opening / closing valve 17a opens the discharge passage 65a as long as the pressing force of the spring 17b acting on the valve is greater than or equal to the pressing force. The operation of the liquid control valve will be described. The state of FIG.
0, 11, 12 are in a non-energized state, and each of the first working chambers 5c, 6c, 7
c and 8c are at atmospheric pressure, and the poppet main valves 5, 6, 7 and 8 are closed by the hydraulic action of the springs 5e, 6e, 7e and 8e and the second working chambers 5d, 6d, 7d and 8d. The cylinder 1 is stopped.
Since the tapered valve portions 5b, 6b, 7b, 8b are seated on the valve seats 5a, 6a, 7a, 8a, the cylinder 1 is stopped and held with very little leakage. Here, the supply flow path P is maintained at a high pressure by the hydraulic pressure from the hydraulic pressure source, and in the differential pressure pilot valve 17, the opening / closing valve 17a is in the open operation state by the pressure from the supply flow path. At this time, the open / close pilot valve 18 becomes the relief valve 18a.
A predetermined current to obtain a predetermined set pressure, and
When the opening / closing valve 18b is also energized so as to open, and the pressure in the load passage B pressurized by the piston of the cylinder 1 loaded in the descending direction reaches an abnormally high pressure and reaches the set pressure, the relief valve 18
a opens, and a differential pressure is generated around the second throttle 8h, which causes the opening / closing valve 18c to open the discharge passage 8m and the second working chamber 8d to the first throttle 8g.
The pressure is reduced to the atmospheric pressure state by the action of, and the poppet main valve 8 is opened by the pressing force based on the differential pressure before and after the second throttle 8h, the load passage B is communicated with the discharge passage R, and the abnormal high pressure is generated. Relief is activated to prevent Since the on-off valve 18b closes at the time of power failure, it loses its function due to the power failure and the relief valve
It is possible to prevent the situation where the discharge passage 8k is opened by 18a and the cylinder 1 descends.

When the cylinder 1 is lifted, the open / close pilot valve 18 is de-energized, and the relief valves 10b, 1 of the first pilot valves 10, 11 are
When a current is applied to 1b, a pressure proportional to the current acts on the first working chambers 6c and 7c of the poppet main valves 6 and 7, and at the same time the second
The second operation chamber 6 in which the operation switching valves 14b and 15b of the pilot valves 14 and 15 are also actuated to switch the switching valves 14a and 15a and the internal fluid is discharged from the discharge passages 6f and 7f.
The d and 7d are brought into the atmospheric pressure state by the action of the first throttles 6g and 7g. Therefore, the poppet main valves 6 and 7 move to positions where the pressing forces of the springs 6e and 7e and the acting forces of the pressures in the first working chambers 6c and 7c are in equilibrium, the valve seats 6a and 7a are opened, and the supply flow is increased. Restrictions corresponding to the positions are formed in the poppet main valves 6 and 7 between the passage P and the load passage B, and between the load passage A and the discharge passage R, respectively, and the liquid from the supply passage P flows from the load passage B. The liquid introduced into the head side chamber 3 of the cylinder 1 and discharged from the rod side chamber 2 of the cylinder 1 passes through the valve seat 7a opened from the load passage A and is discharged into the discharge passage R to raise the cylinder 1.

Depending on the energization value of the relief valves 10b, 11b, the poppet main valve 6,
Since the position of 7 is determined, the energization value can be appropriately determined to adjust the piston rising speed of the cylinder 1. At this time, when another actuator having an operating pressure lower than that of the cylinder 1 is operated by the liquid from the hydraulic pressure source, the pressure in the supply passage P becomes smaller than the pressure in the load passage B, and the differential pressure pilot valve 17 opens / closes the opening / closing valve 17a. Is closed by the spring 17b, the second part of the poppet main valve 6
The working chamber rises to the pressure of the load flow path B and the poppet main valve 6
Closes the valve seat 6a and prevents the piston of the cylinder 1 from descending.

When the first pilot valves 10 and 11 are de-energized and the first pilot valves 9 and 12 are energized, the second pilot valves 14 and 15 are returned to the normal position as shown in FIG. 1 and the poppet main valve 6,
When 7 is closed, the pressure proportional to the value of the electric current to be applied acts on the poppet main valves 5 and 8 respectively, and the opening / closing switching valves 13a and 16a of the second pilot valves 13 and 16 are opened similarly to the second operation. The working chambers 5d and 8d are brought to the atmospheric pressure state, the poppet main valves 5 and 8 are opened, and the cylinder 1 is lowered.
As with the ascent, the piston descent speed of the cylinder 1 can be adjusted by appropriately setting the energization value to the relief valves 9b, 12b.

In the state of FIG. 1, when the hydraulic pump is unloaded and the supply passage P is at low pressure, the pilot valves 10 and 11 are
Even when the hydraulic pump is on-loaded to supply the hydraulic pressure to the supply passage P at the same time as the energization of the power supply, even if the open / close switching valve 14a is opened, the pressure in the supply passage P is lower than the pressure in the load passage B. Spring 17
Unless the pressure is increased to b for the time being, the opening / closing valve 17a does not open and the poppet main valve 6 does not open.
Can be prevented from falling.

Further, instead of providing the differential pressure pilot valve 17, the first pilot valve 6 of the poppet main valve 6 is provided in the second pilot valve 14 as shown in FIG.
Open / close switching valve 14d that applies the pressure from the hydraulic chamber 63 in the closing direction
Works as well.

[Effect of device]

Thus, the present invention has a valve seat interposed between a supply flow passage connected to a hydraulic pressure source and a load flow passage connected to an actuator,
It has a valve part that is seated so as to close the valve seat, and the poppet main valve that opens and closes the valve seat by movement, a spring that presses the poppet main valve in the direction to close the valve seat, and a valve inside the poppet main valve by hydraulic pressure. A first working chamber that exerts a pressing force in the direction to open the seat, a first pilot valve that applies hydraulic pressure to the first working chamber to open the poppet main valve, and a load passage through a throttle, When the communication to the low pressure side is cut off, the poppet main valve is pressed by the internal hydraulic pressure to close the valve seat, and when the communication to the low pressure side is made, the second action to cancel the pressing by the hydraulic pressure is performed. And a second pilot chamber that is provided in the discharge passage that connects the second working chamber to the low pressure side and that opens the second working chamber so as to communicate with the low pressure side when the poppet main valve is opened. , When the load flow path is higher than the supply flow path, the second working chamber and low pressure And a valve mechanism that closes so as to cut off communication with the second flow chamber, and when the load flow passage becomes higher in pressure than the supply flow passage, the valve mechanism closes and the second working chamber rises to the pressure of the load flow passage. Then, the poppet main valve is moved in the closing direction to close the valve seat to shut off the two flow passages, and the valve mechanism provided in the discharge passage of the second working chamber can be made into a small shape for the small flow rate control. It is possible to prevent the control device from increasing in size.

[Brief description of drawings]

FIG. 1 is an overall configuration diagram showing an embodiment of a fluid control device according to the present invention, and FIG. 2 is a first diagram of the device shown in FIG.
FIG. 3 is a detailed enlarged cross-sectional view of the poppet main valve portion, FIG. 3 is an enlarged view of a main part showing another embodiment of the liquid control device according to the present invention, and FIG. 4 is an overall configuration diagram showing a conventional example. P ... Supply flow path, B ... Load flow path, 6 ... Poppet main valve, 6a ... Valve seat, 6b ... Valve part, 6c ... First working chamber, 6d ...
… Second working chamber, 6e …… Spring, 6f …… Discharge path, 10 …… First
Pilot valve, 14 …… Second pilot valve, 14d, 17 ……
Valve mechanism.

Claims (1)

[Scope of utility model registration request] 1. A valve seat which is interposed between a supply flow path connected to a hydraulic pressure source and a load flow path connected to an actuator, and a valve portion which is seated so as to close the valve seat, and the valve seat is opened and closed by movement. Poppet main valve, a spring that presses the poppet main valve in the direction to close the valve seat, a first working chamber that applies a pressing force to the poppet main valve in the direction to open the valve seat by the internal hydraulic pressure, and the poppet main valve Is connected to the load flow path through a throttle and a first pilot valve that applies hydraulic pressure to the first working chamber to open the valve, and when the communication to the low pressure side is cut off, the poppet main valve is turned on by the internal hydraulic pressure. A second working chamber that presses to close the valve seat and eliminates the pressing by the hydraulic pressure when communication with the low pressure side is made, and a discharge passage that connects the second working chamber to the low pressure side,
A second pilot valve that opens the second working chamber so as to communicate with the low pressure side when the poppet main valve is opened, and a second pilot chamber that is provided in this discharge passage and has a load passage higher in pressure than the supply passage. And a valve mechanism that closes so as to cut off communication between the low pressure side and the low pressure side.