JP2008030896A - Actuator control device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent shock even when rapidly switching a main spool MS. <P>SOLUTION: In a valve element 5, a sub-valve element 35 is movably provided in a passage course communicating an actuator port with a pressure chamber 7. In the sub-valve element 35, a first control orifice 37 and a second control orifice 38 are provided. Opening diameter of the first control orifice 37 is set smaller than that of the second control orifice 38. Spring force of a spring 40 is applied to one side face of the sub-valve element 35, and normally the second control orifice 38 is opened due to the action of the spring force of the spring 40. Due to the action of a pressure difference generated before and after the second control orifice 38 caused by a flow of fluid flowing from the actuator port to the pressure chamber 7, the sub-valve element 35 resists to the spring force of the spring 40 and is moved, so as to open only the first control orifice 37. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an actuator control device suitable for controlling a lowering operation of a lift cylinder in, for example, a forklift.

  As this type of apparatus, the present applicant has proposed the apparatus shown in Patent Document 1, and FIGS. 2 to 4 show this apparatus. This conventional device is assumed to control a lift cylinder of a forklift. In the valve body B, an actuator port 1 connected to the lift cylinder and a spool hole 2 into which a main spool MS is slidably incorporated. Is forming. The valve body B incorporates an operation check valve V, and the actuator port 1 communicates with the supply passage 3 and the return passage 4 through the operation check valve V. In other words, the operation check valve V is provided at the junction of the supply passage 3 and the return passage 4.

  The operation check valve V is configured to open and close the seat portion 6 provided in the valve body B by a poppet portion 5 a provided in the valve body 5. When the seat portion 6 is opened, the actuator port 1 communicates with the supply passage 3 and the return passage 4. When the seat portion 6 is closed, the actuator port 1 communicates with the supply passage 3 and the return passage 4. It is configured to be blocked.

  Further, the operation check valve V is provided with a cylindrical portion 5b on the side opposite to the poppet portion 5a, and this cylindrical portion 5b faces the pressure chamber 7. A control orifice 8 is formed in the cylindrical portion 5 b, and the pressure chamber 7 is always in communication with the actuator port 1 through the control orifice 8. Further, a spring 9 is provided in the pressure chamber 7, and normally, the poppet portion 5 a closes the seat portion 6 by the action of the spring force of the spring 9.

  In the operation check valve V as described above, the diameter of the cylindrical portion 5 b is larger than the diameter of the seat portion 6. Therefore, if the pressure acting on the outer periphery of the poppet portion 5a is equal to the pressure acting on the cylinder portion 5b when the poppet portion 5a closes the seat portion 6, in other words, the actuator port 1 and the pressure chamber 7 If the pressures are equal, the seat portion 6 is closed by the poppet portion 5a, and the operation check valve V is kept closed.

  On the other hand, a supply-side annular groove 10 and a return-side annular groove 11 are formed in the main spool MS. The supply-side annular groove 10 is always in communication with a pump passage 12 communicated with a pump (not shown), and when the main spool MS is moved from the neutral position shown in the drawing to the right in the drawing, the supply-side annular groove 10 passes through the supply-side annular groove 10. Thus, the pump passage 12 and the supply passage 3 are communicated with each other. The return-side annular groove 11 allows the return passage 4 and the tank passage 13 to communicate with each other when the main spool MS moves from the neutral position shown in the drawing to the left.

  The main spool MS described above incorporates a pilot spool PS, and first to third ports 14 to 16 are formed in a positional relationship corresponding to the pilot spool PS. The first port 14 is closed when the main spool MS is at the neutral position shown in the figure, and when the main spool MS moves from the neutral position to the left in the drawing, that is, in the direction to return the fluid from the actuator, The pressure chamber 7 communicates with the pressure chamber 7.

  The second port 15 is closed when the main spool MS is in the neutral position shown in the drawing, and when the main spool MS moves in the left direction in the drawing as described above, the annular groove 18 formed in the inner surface of the spool hole 2. The tank passage 13 communicates with the tank. Further, the third port 16 is closed when the main spool MS is in the neutral position shown in the figure, and communicates with the return passage 4 when the main spool MS moves in the left direction of the drawing as described above.

  The first to third ports 14 to 16 configured as described above maintain the following positional relationship. That is, when the main spool MS is moved from the neutral position to the left in the drawing, first, the second port 15 communicates with the annular groove 18, and then the first port 14 enters the pressure chamber 7 via the flow path 17. At the same time, the third port 16 communicates with the return passage 4. After the third port 16 communicates with the return passage 4, as shown in FIGS. 2 and 3, the relative relationship that the return passage 4 and the tank passage 13 communicate with each other through the notch 19 formed in the main spool MS is established. I keep it.

  Further, the pilot spool PS incorporated in the main spool MS has one end facing the pilot chamber 20 and the other end facing the spring chamber 21. A spring 22 is provided in the spring chamber 21, and the pilot spool PS is normally pressed against the end surface of the pilot chamber 20 by the spring force of the spring 22. The spring chamber 21 is always in communication with the second port 15 via a communication passage 23 formed in the main spool MS. Therefore, when the second port 15 communicates with the annular groove 18, the spring chamber 21 also communicates with the tank passage 13 via the annular groove 18.

  The pilot spool PS as described above is formed with an annular recess 24, and this annular recess 24 is always in communication with the pilot chamber 20 via a control throttle 25 formed in the pilot spool PS.

  When the pilot spool PS is in the illustrated normal position due to the spring force of the spring 22, the second port 15 is closed by the first land portion 26 formed in the pilot spool PS.

  In the figure, reference numeral 28 denotes a centering spring which keeps the main spool MS at the neutral position shown in the figure. Reference numeral 29 denotes a load check valve provided in the supply passage 3 and allows only the flow from the pump passage 12 to the actuator port 1.

  Next, the operation of this apparatus will be described. When the main spool MS is at the neutral position shown in the figure, the supply passage 3 is disconnected from the pump passage 12 and the return passage 4 is connected to the tank passage 13. Is disconnected. In addition, in this state, the pressure chamber 7 of the operation check valve V is also disconnected from the tank passage 13. Therefore, the load pressure guided to the actuator port 1 acts on the outer periphery of the valve body 5 and also acts on the cylinder portion 5 b in the pressure chamber 7. However, as described above, since the pressure receiving area of the cylinder portion 5b in the pressure chamber 7 is larger than the pressure receiving area of the outer periphery of the valve body 5 that closes the seat portion 6, the operation check valve V is kept closed. .

  When the main spool MS is moved from the neutral position to the right in the drawing, the supply passage 3 communicates with the pump passage 12 through the supply-side annular groove 10. Therefore, the pressure fluid supplied to the supply passage 3 passes through the load check valve 29 and pushes open the operation check valve V to be supplied from the actuator port 1 to the actuator.

  On the other hand, when the main spool MS is moved from the neutral position to the left in the drawing, first, the second port 15 communicates with the tank passage 13 via the annular groove 18. In this state, when the main spool MS is further moved leftward, the first port 14 is now communicated with the pressure chamber 7 via the flow path 17. Therefore, the load holding pressure of the pressure chamber 7 is guided to the pilot chamber 20 through the annular recess 24 and the control throttle 25.

  As described above, when the load holding pressure of the pressure chamber 7 is guided to the pilot chamber 20, since the spring chamber 21 is held at the tank pressure, the pilot spool PS moves against the spring force of the spring 22. When the pilot spool PS moves in this way, as shown in FIG. 3, the first port 14 and the second port 15 communicate with each other via the annular recess 24, so that the pressure chamber 7 is connected to the flow path 17 → first. It communicates with the tank passage 13 via the port 14 → the annular recess 24 → the second port 15. Therefore, the operation check valve V is opened by the load pressure acting on the pressure receiving area on the outer periphery of the valve body 5, the poppet portion 5 a opens the seat portion 6, and the working fluid of the actuator port 1 flows out to the return passage 4 side. Let

  As described above, the first port 14 and the flow path 17 communicate with each other, and at the same time, the third port 16 communicates with the return path 4, so that the fluid in the return path 4 flows into the pilot chamber 20. As is clear from FIG. 4, the fluid flowing into the pilot chamber 20 flows into the tank passage 13 via the control throttle 25 → the annular recess 24 → the second port 15 → the annular groove 18. When a flow is generated in the control throttle 25 as described above, a differential pressure is generated before and after the control throttle 25 and the upstream pressure acts on the pilot chamber 20.

  Therefore, the pilot spool PS maintains a position where the pressure in the pilot chamber 20 and the spring force of the spring 22 are balanced, and at the balance position, the opening degree of the first port 14 is controlled as shown in FIG. . Since the pilot spool PS maintains the balance position in this way, the opening degree of the first port 14 is controlled, so that the pressure in the pressure chamber 7 is also kept constant. Thus, if the pressure in the pressure chamber 7 is kept constant, hunting of the operation check valve V is reliably prevented.

In addition, since the inching control can be performed using the notch 19 while the pressure in the return passage 4 is stably maintained, the inching control can be performed smoothly. If the notch 19 is opened in the return passage 4 as described above, the flow rate proportional to the opening of the notch 19 can be returned to the tank passage 13.
Japanese Patent Application No. 2005-360741

  In the conventional apparatus as described above, for example, when the operation check valve is fully opened and the lift cylinder is being raised or fully lifted, the main spool MS is immediately switched to the lowered position. The operation check valve V sometimes did not return completely. This is because the pressure in the pressure chamber 7 cannot be kept sufficiently high due to the influence of the control orifice 8. If the operation check valve V does not completely return in this way, almost all of the return flow rate from the actuator flows into the return passage 4 and a large pressure loss occurs at the opening of the return side annular groove 11 with respect to the return passage 4. To do. There was a problem that the greater the pressure loss, the greater the shock.

  An object of the present invention is to provide an apparatus with less shock even when, for example, a lift cylinder is raised and then immediately switched to a lowering mode.

  According to the present invention, a main spool is slidably provided in the valve body, and an actuator port formed in the valve body is connected to a supply passage or a return passage according to a moving position of the main spool. The operation check valve is provided at the joining portion of the supply passage and the return passage, the operation check valve includes a seat portion provided at the joining portion of the supply passage and the return passage, a valve body incorporated in the valve body, A poppet part formed on the valve body for opening and closing the seat part, a pressure chamber facing the valve body on the opposite side of the poppet part, and a valve body formed on the valve body, wherein the actuator port communicates with the pressure chamber. And a spring that is provided in the pressure chamber and exerts a spring force in a direction in which the poppet portion is pressed against the seat portion. Actuator control device that increases the diameter of the valve body in the pressure chamber with respect to the opening diameter of the part and connects the pressure chamber to the tank passage or shuts off the communication according to the movement position of the main spool On the premise.

  Based on the above apparatus, the present invention provides the valve body, wherein the sub-valve body is movably provided in the passage process that communicates the actuator port and the pressure chamber. The first control orifice and the second control orifice are provided, the opening diameter of the first control orifice is made smaller than the opening diameter of the second control orifice, and the spring force of the spring acts on one side surface of the sub valve body. Usually, the second control orifice is opened by the action of the spring force of the spring, and the sub-valve element is acted on by the differential pressure generated before and after the second control orifice by the flow of fluid flowing from the actuator port to the pressure chamber. Is characterized in that it moves against the spring force of the spring and opens only the first control orifice.

  According to the present invention, the second control orifice having the larger opening diameter is opened first, and then the first control orifice having the smaller opening diameter is opened. Therefore, the pressure in the pressure chamber is instantaneously increased, and the operation in the closing direction is performed. This increases the responsiveness of the check valve. Thus, if the responsiveness of the operation check valve is improved, the above-described conventional defects are eliminated.

  The embodiment shown in FIG. 1 is substantially the same as the conventional device except that the sub valve body 35 is incorporated in the valve body 5 of the conventional device described above. In the following, portions overlapping with those in the prior art will be described in detail, and the same constituent elements as those in the prior art will be described with overlapping reference numerals.

  The apparatus of this embodiment assumes a case where a lift cylinder of a forklift is controlled. In the valve body B, an actuator port 1 connected to the lift cylinder and a spool hole 2 into which a main spool MS is slidably incorporated. And form. The valve body B incorporates an operation check valve V, and the actuator port 1 communicates with the supply passage 3 and the return passage 4 through the operation check valve V. In other words, the operation check valve V is provided at the junction of the supply passage 3 and the return passage 4.

  The operation check valve V is configured to open and close the seat portion 6 provided in the valve body B by a poppet portion 5 a provided in the valve body 5. When the seat portion 6 is opened, the actuator port 1 communicates with the supply passage 3 and the return passage 4. When the seat portion 6 is closed, the actuator port 1 communicates with the supply passage 3 and the return passage 4. It is configured to be blocked.

  Further, the operation check valve V is provided with a cylindrical portion 5b on the side opposite to the poppet portion 5a, and this cylindrical portion 5b faces the pressure chamber 7. The poppet portion 5a is formed with a valve hole 30 along the axis of the cylinder portion 5b. The valve hole 30 is always in communication with the actuator port 1 through a port 31. The valve hole 30 thus configured is fitted with a plug 32, and a recess 33 formed in the plug 32 is communicated with the pressure chamber 7 through a passage 34 formed in the plug 32.

  The sub-valve element 35 is slidably incorporated in the recess 33 as described above. The sub-valve element 35 has an introduction port 36 opened around the sub-valve element 35 and an axis of the sub-valve element 35. A first control orifice 37 is formed, and a second control orifice 38 communicating with the first control orifice 37 in series and having a larger diameter than the first control orifice 37 is formed. A spring chamber 39 is formed between the sub valve body 35 and the bottom of the recess 33, and a spring 40 is interposed in the spring chamber 39. Further, a pilot chamber 41 is formed on the opposite side of the spring chamber 39 with the sub valve body 35 interposed therebetween. The pilot chamber 41 is interposed via the first control orifice 37, the second control orifice 38 and the spring chamber 39. To the pressure chamber 7.

The sub valve body 35 configured as described above maintains the illustrated normal position by the action of the spring force of the spring 40 as long as no pressure acts on the pilot chamber 41. The sub valve body 35 in the normal position opens the introduction port 36 and allows the actuator port 1 to communicate with the pressure chamber 7 via the introduction port 36 and the second control orifice 38. When a fluid flows through the second control orifice 38 and a differential pressure is generated across the orifice 38, the sub valve body 35 moves against the spring 40 and closes the introduction port 36.
Further, a spring 9 is provided in the pressure chamber 7, and normally, the poppet portion 5 a closes the seat portion 6 by the action of the spring force of the spring 9.

  In the operation check valve V as described above, the diameter of the cylindrical portion 5 b is larger than the diameter of the seat portion 6. Therefore, if the pressure acting on the outer periphery of the poppet portion 5a is equal to the pressure acting on the cylinder portion 5b when the poppet portion 5a closes the seat portion 6, in other words, the actuator port 1 and the pressure chamber 7 If the pressures are equal, the seat portion 6 is closed by the poppet portion 5a, and the operation check valve V is kept closed.

  On the other hand, a supply-side annular groove 10 and a return-side annular groove 11 are formed in the main spool MS. The supply-side annular groove 10 is always in communication with a pump passage 12 communicating with the pump as in the prior art, and when the main spool MS is moved from the neutral position in the drawing to the right in the drawing, the supply-side annular groove 10 is interposed via the supply-side annular groove 10. Thus, the pump passage 12 and the supply passage 3 are communicated with each other. The return-side annular groove 11 allows the return passage 4 and the tank passage 13 to communicate with each other when the main spool MS moves from the neutral position shown in the drawing to the left. Although FIG. 1 showing this embodiment does not show the supply-side annular groove 10 and the pump passage 12, FIG. 2 is also used in this embodiment as it is.

  The main spool MS described above incorporates a pilot spool PS, and first to third ports 14 to 16 are formed in a positional relationship corresponding to the pilot spool PS. The first port 14 is closed when the main spool MS is at the neutral position shown in the figure, and when the main spool MS moves from the neutral position to the left in the drawing, that is, in the direction to return the fluid from the actuator, The pressure chamber 7 communicates with the pressure chamber 7.

  The second port 15 is closed when the main spool MS is in the neutral position shown in the drawing, and when the main spool MS moves in the left direction in the drawing as described above, the annular groove 18 formed in the inner surface of the spool hole 2. The tank passage 13 communicates with the tank. Further, the third port 16 is closed when the main spool MS is in the neutral position shown in the figure, and communicates with the return passage 4 when the main spool MS moves in the left direction of the drawing as described above.

  The first to third ports 14 to 16 configured as described above maintain the following positional relationship. That is, when the main spool MS is moved from the neutral position to the left in the drawing, first, the second port 15 communicates with the annular groove 18, and then the first port 14 enters the pressure chamber 7 via the flow path 17. At the same time, the third port 16 communicates with the return passage 4. After the third port 16 communicates with the return passage 4, as shown in FIGS. 2 and 3, the relative relationship that the return passage 4 and the tank passage 13 communicate with each other through the notch 19 formed in the main spool MS is established. I keep it.

  Further, the pilot spool PS incorporated in the main spool MS has one end facing the pilot chamber 20 and the other end facing the spring chamber 21. A spring 22 is provided in the spring chamber 21, and the pilot spool PS is normally pressed against the end surface of the pilot chamber 20 by the spring force of the spring 22. The spring chamber 21 is always in communication with the second port 15 via a communication passage 23 formed in the main spool MS. Therefore, when the second port 15 communicates with the annular groove 18, the spring chamber 21 also communicates with the tank passage 13 via the annular groove 18.

  The pilot spool PS as described above is formed with an annular recess 24, and this annular recess 24 is always in communication with the pilot chamber 20 via a control throttle 25 formed in the pilot spool PS.

When the pilot spool PS is in the illustrated normal position due to the spring force of the spring 22, the second port 15 is closed by the first land portion 26 formed in the pilot spool PS.
The centering spring 28 and the load check valve 29 are provided as in the conventional case.

  Next, the operation of this apparatus will be described. When the main spool MS is in the neutral position shown in the figure, the supply passage 3 is disconnected from the pump passage 12, and the return passage 4 is connected to the tank passage 13. Is disconnected. In addition, in this state, the pressure chamber 7 of the operation check valve V is also disconnected from the tank passage 13. Therefore, the load pressure guided to the actuator port 1 acts on the outer periphery of the valve body 5 and also acts on the cylinder portion 5 b in the pressure chamber 7. However, as described above, since the pressure receiving area of the cylinder portion 5b in the pressure chamber 7 is larger than the pressure receiving area of the outer periphery of the valve body 5 that closes the seat portion 6, the operation check valve V is kept closed. .

  When the main spool MS is moved from the neutral position to the right in the drawing, the supply passage 3 communicates with the pump passage 12 through the supply-side annular groove 10. Therefore, the pressure fluid supplied to the supply passage 3 passes through the load check valve 29 and pushes open the operation check valve V to be supplied from the actuator port 1 to the actuator.

  When the main spool MS is returned to the neutral position from the above state, the second port 15 is disconnected from the annular groove 18, the first port 14 is connected to the flow path 17, and the flow path 17 is disconnected from the tank passage 13. The When the communication between the flow path 17 and the tank passage 13 is cut off in this way, the pressure on the pressure chamber 7 and the actuator port 1 side becomes equal, and the valve body 5 returns to the closed position by the spring force of the spring 9. At this time, since the spring chamber 39 and the pilot chamber 41 partitioned by the sub valve body 35 are also at the same pressure, the sub valve body 35 is maintained at the illustrated normal position by the action of the spring force of the spring 40. Become.

  On the other hand, when the main spool MS is moved from the neutral position to the left in the drawing, first, the second port 15 communicates with the tank passage 13 via the annular groove 18. In this state, when the main spool MS is further moved leftward, the first port 14 is now communicated with the pressure chamber 7 via the flow path 17. Therefore, the load holding pressure of the pressure chamber 7 is guided to the pilot chamber 20 through the annular recess 24 and the control throttle 25.

  As described above, when the load holding pressure of the pressure chamber 7 is guided to the pilot chamber 20, since the spring chamber 21 is held at the tank pressure, the pilot spool PS moves against the spring force of the spring 22. When the pilot spool PS moves in this way, as shown in FIG. 3, the first port 14 and the second port 15 communicate with each other via the annular recess 24, so that the pressure chamber 7 is connected to the flow path 17 → first. It communicates with the tank passage 13 via the port 14 → the annular recess 24 → the second port 15.

  When the pressure chamber 7 communicates with the tank passage 13 as described above, the actuator port 1 also communicates with the pressure chamber 7 via the introduction port 36 → the second control orifice 38 → the spring chamber 39. A flow is generated in the orifice 38. If a flow is generated in the second control orifice 38 in this way, a pressure difference is generated between the pilot chamber 41 and the spring chamber 39 due to the pressure loss, and the sub-valve element 35 is caused by the spring force of the spring 40. It moves against and closes the introduction port 36. When the introduction port 36 is closed in this way, the actuator port 1 is now in communication with the pressure chamber 7 via the first control orifice 37. Therefore, the operation check valve V is opened by the load pressure acting on the pressure receiving area on the outer periphery of the valve body 5, the poppet portion 5 a opens the seat portion 6, and the working fluid of the actuator port 1 flows out to the return passage 4 side. Let

  As described above, the first port 14 and the flow path 17 communicate with each other, and at the same time, the third port 16 communicates with the return path 4, so that the fluid in the return path 4 flows into the pilot chamber 20. As is clear from FIG. 4, the fluid flowing into the pilot chamber 20 flows into the tank passage 13 via the control throttle 25 → the annular recess 24 → the second port 15 → the annular groove 18. When a flow is generated in the control throttle 25 as described above, a differential pressure is generated before and after the control throttle 25 and the upstream pressure acts on the pilot chamber 20.

  Therefore, the pilot spool PS maintains a position where the pressure in the pilot chamber 20 and the spring force of the spring 22 are balanced, and at the balance position, the opening degree of the first port 14 is controlled as shown in FIG. . Since the pilot spool PS maintains the balance position in this way, the opening degree of the first port 14 is controlled, so that the pressure in the pressure chamber 7 is also kept constant. Thus, if the pressure in the pressure chamber 7 is kept constant, hunting of the operation check valve V is reliably prevented.

  In addition, since the inching control can be performed using the notch 19 while the pressure in the return passage 4 is stably maintained, the inching control can be performed smoothly. Further, if the notch 19 is opened in the return passage 4 as described above, a flow rate proportional to the opening of the notch 19 can be returned to the tank passage 13.

  Next, the main spool MS is moved in the right direction in the drawing as described above, and the main spool MS is immediately switched to the left in the drawing beyond the neutral position from the state in which the valve body 5 is opened, and the return passage 4 Will be described in connection with the tank passage 13 via the return-side annular groove 11. In the above case, if the return passage 4 and the tank passage 13 communicate with each other when the valve body 5 is not sufficiently closed, the return fluid on the actuator side causes a wrap portion between the return passage 4 and the return-side annular groove 11. The pressure loss at the lap portion increases abruptly. Therefore, in this embodiment, the valve body 5 is smoothly returned to the control state in the above case.

  That is, in the state where the return passage 4 and the tank passage 13 are in communication as described above, the pressure chamber 7 is also in communication with the tank passage 13 as described above. At this time, the sub-valve element 35 maintains the illustrated normal state by the action of the spring 40 and keeps the introduction port 36 open. Therefore, the actuator port 1 communicates with the pressure chamber 7 via the introduction port 36 and the second control orifice 38, and a flow is generated in the second control orifice 38. However, the opening area of the second control orifice 38 is larger than that of the first control orifice 37 and the valve body 5 is opened larger than the control state, so that the pressure chamber 7 and the actuator port 1 are combined. The pressure difference with is not so large. Therefore, the valve body 5 smoothly returns to the control state by the action of the spring force of the spring 9.

When the valve body 5 returns to the control state as described above and the opening of the seat portion 6 is reduced to some extent, the sub valve body 35 is moved to the spring 40 by the action of the pressure loss of the fluid passing through the second control orifice 38. It moves against and closes the introduction port 36. Therefore, after that, the first control orifice 37 functions and normal control is performed.
The sub-valve element 35 is set so as to switch with respect to the pilot flow rate when the lift is raised, and not to switch with respect to the flow rate supplied to the pressure chamber 7 when the valve element 5 is seated. If the sub valve body 35 is not switched, the return of the sub valve body 35 is accelerated because the orifice 38 is open. Therefore, even if the supply mode in which the pressure fluid is supplied from the supply passage 3 to the actuator port 1 as in the prior art and the return mode in which the working fluid is returned from the actuator port 1 to the return passage 4 are suddenly switched, Since 5 smoothly returns to the control state, the shock is mitigated as compared with the conventional case.

It is sectional drawing of the principal part which shows embodiment of this invention. FIG. 10 is a cross-sectional view showing a conventional device in a state where a main spool is kept in a neutral position. FIG. 9 is a partial enlarged cross-sectional view showing a conventional device, in which a main spool is switched to a left position in the drawing and a first port is fully opened. FIG. 9 is a partial enlarged cross-sectional view showing a conventional device, in which a main spool is switched to a left position in the drawing and a first port is in a controlled state.

Explanation of symbols

B Valve body 1 Actuator port MS Main spool V Operation check valve 3 Supply passage 4 Return passage 5 Valve body 5a Poppet portion 6 Seat portion 7 Pressure chamber 9 Spring 13 Tank passage 35 Sub valve body 37 First control orifice 38 Second control orifice 40 Spring

Claims (1)

  A main spool is slidably provided in the valve body, and an actuator port formed in the valve body communicates with the supply passage or communicates with the return passage according to the movement position of the main spool. An operation check valve is provided at the junction between the supply passage and the return passage. The operation check valve includes a seat provided at the junction between the supply passage and the return passage, a valve body incorporated in the valve body, and a valve body. A poppet part that opens and closes the seat part, a pressure chamber facing the valve body on the opposite side of the poppet part, an orifice that is formed in the valve body and communicates the actuator port and the pressure chamber; A spring provided in the pressure chamber to exert a spring force in a direction in which the poppet portion is pressed against the seat portion, and the opening diameter of the seat portion is provided. On the other hand, in the actuator control device that increases the diameter of the valve body in the pressure chamber and connects the pressure chamber to the tank passage or shuts off the communication according to the movement position of the main spool. The sub-valve body is movably provided in the passage process that connects the actuator port and the pressure chamber, and the sub-valve body is provided with a first control orifice and a second control orifice, The opening diameter of the control orifice is made smaller than the opening diameter of the second control orifice, and the spring force of the spring is applied to one side surface of the sub-valve body. Action of differential pressure generated before and after the second control orifice by the flow of fluid flowing from the actuator port to the pressure chamber while the control orifice is opened , Sub-valve body is moved against the spring force of the spring, an actuator control device that only the first control orifice configuration which opens.

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