JP2008309318A - Slow return device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a slow return device capable of removing the influence of instability in manual operation and establishing a stable control while realizing reduction of size. <P>SOLUTION: The slow return device includes a valve body B, a valve accommodation part 4 bored inside the valve body B, a first port 1 communicating with a actuator, and a second port 2 in communication to a fluid source or a tank, wherein a first seat part 11 to be opened and closed by a first valve element 5 is formed on the inner wall of the valve accommodation part 4 while a second seat part 14 to be opened and closed by a second valve element 6 is formed on one part 5 of the first valve element, and it is arranged so that the end of a rod member 15 penetrating a through hole bored in the first valve element 5 confronts a pilot piston 10 installed in a pilot chamber 7 formed at the other end of the valve accommodation part 4, and further the first valve element 5 is furnished with a throttle hole 13 for limiting the flow of the fluid flowing from the first port 1 to the second port 2 via the second seat part 14 when the second valve element 6 opens the second seat part 14. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a slow return device that slows down movement in a reciprocating motion of a construction machine or the like by a control flow by a throttle valve in one direction, for example, when descending.

  Conventionally, a slow return device having a check valve and a slow return valve has been used in order to prevent a sudden drop when the hydraulic lift device or the like is lowered. This slow return device is connected to an actuator such as an elevating cylinder and becomes free flow when supplying hydraulic oil to the actuator through the connection passage, but when returning fluid from the actuator to the tank when descending, The control flow is created by the throttle of the slow return valve.

In order to reduce the size of such a device, for example, as in the device described in Patent Document 1, a device in which a check valve, a slow return valve, and a stop valve are integrally provided in a valve body in a valve case. It has been known.
The conventional apparatus described in Patent Document 1 has a main part configured as shown in FIG. FIG. 4 shows a state in which a control flow from the port 32 to 31 for controlling the return fluid from the cylinder occurs when the cylinder is lowered.

As shown in FIG. 4, in the conventional apparatus, a port 31 connected to a fluid source or a tank and a port 32 connected to the actuator side are formed in the valve case 20a.
The valve case 20a includes a first seat portion 82 that constitutes a stop valve, a first poppet portion 80 that opens and closes the first seat portion 82, and a poppet having the first poppet portion 80. And a second poppet part 81 that opens and closes the second sheet part 83 formed on 28.
The second poppet part 81 is formed at the tip of the screw tool 22 that moves in the axial direction by manual operation, and the position of the second poppet part 81 is adjusted by operating the screw tool 22. Further, a pressing force in the direction of the second poppet portion 81 is applied to the first poppet 28 by a spring 29.

When supplying hydraulic oil from the port 31 to the port 32 with such an apparatus, the operator manually turns the screw tool 22 to move it to the left in the figure. At this time, if the first poppet 28 is pulled by the pin 26 fixed to the screw tool 22 and moved until the first sheet portion 82 is fully opened, the free flow through the first sheet portion 82 is achieved. The hydraulic fluid is quickly supplied to the actuator.
Further, when the communication between the port 31 and the port 32 is blocked, the screw tool 22 is moved to the right side in the drawing, and the poppet 28 is moved with the second poppet portion 81 closing the second sheet portion 83. Push. Then, the first sheet portion 82 is closed by the first poppet portion 80, and both the first and second sheet portions 82 and 83 are closed.

Furthermore, the control flow state shown in FIG. 4 is as follows.
The operator rotates the screw tool 22 by manual operation and moves it to the left in the figure to determine the position of the second poppet portion 81. The first poppet 28 moves from the port 31 side by the pressure on the high-pressure port 32 side until the second sheet portion 83 hits the second poppet portion 81. When the first poppet 28 moves until it abuts against the second poppet portion 81, the first sheet portion 82 opens, and the aperture 92 is configured by this opening. That is, the movement amount of the first poppet 28 is limited by the position of the second poppet portion 81 adjusted by the screw portion 22, and thereby the opening degree of the first sheet portion 82 is adjusted to form the diaphragm 92.
JP 2001-54302 A

As described above, in the apparatus of Patent Document 1, manual operation is required to open / close or control communication between ports. Therefore, there is a problem that not only the operation is troublesome for the operator, but also the switching timing and control are not constant.
In particular, when creating a control flow, the screw member 22 is manually operated, the first seat portion 82 provided in the valve case 20a is slightly opened, and the control flow is generated using the opening as a restriction 92. Yes. As described above, since opening / closing of the diaphragm and control of the diaphragm amount must be performed manually, instability of manual operation directly affects diaphragm control. For example, when the rotation speed or rotation amount of the screw tool 22 by the operator is not constant, there is a possibility that the flow rate control at the time of slow return is not reproducible and the cylinder lowering speed cannot be sufficiently controlled. is there.

  The object of the present invention is to integrate a check valve and a slow return valve into the same body so as to enable downsizing, while eliminating the influence of instability in manual operation and enabling a stable return. Is to provide a device.

  According to a first aspect of the present invention, there is provided a valve body, a valve housing portion bored in the valve body, a first port which is pierced at one end side of the valve housing portion and communicates with the actuator side, and is bored in the valve housing portion And a second port communicating with the fluid source or the tank, and a first seat that is opened and closed by a first valve body that moves in an opening direction by a fluid pressure from the second port on the inner wall of the valve housing portion The first valve body is provided with a second seat part that is opened and closed by the second valve body, and a rod member linked to the second valve body is freely movable in the first valve body. A pilot piston disposed in the pilot chamber so that the end portion of the rod member protrudes into the pilot chamber formed on the other end side of the valve housing portion, and is movably disposed in the pilot chamber. Confrontation And when the second valve body opens the second seat portion, the first valve body has a throttle hole for restricting the flow of fluid flowing from the first port to the second port through the second seat portion. When the pilot pressure is guided to the pilot chamber with the tank connected to the second port, the first seat portion is closed by the pressure action, and the pilot piston and the rod member are interposed. The second valve body opens the second seat portion by the pilot pressure acting, and a control flow from the first port to the second port is generated through the throttle hole, and a tank is connected to the second port, and When pilot pressure is not guided to the pilot chamber, the first seat portion and the second seat portion are closed by pressure action, the communication between the first port and the second port is shut off, and the first When connecting the fluid source to the port, the first sheet portion is opened by the pressure action, and wherein the point of free flow through the first sheet portion has a configuration that occurs.

  The second invention is premised on the first invention, and is characterized in that an elastic member for applying a force in a direction to close the second seat portion is applied to the second valve body.

According to the first and second inventions, the valve mechanism necessary for controlling the flow of fluid between the first port and the second port connected to the actuator is integrally provided in one valve body. Therefore, the apparatus can be downsized and the flow path can be switched only by the pressure action, so that manual operation is not required.
In particular, when the control flow is formed, switching to a flow path having a throttle with a fixed opening is performed by pressure action, so that the throttle control by manual operation is not performed as in the conventional device. Unnecessary and stable control is possible.
According to the second invention, the second valve body can easily follow the operation of the first valve body, and the second seat portion can be reliably closed in a state where the pilot pressure is not guided.

1 to 3 show an embodiment of the present invention.
This device has a first port 1 connected to a valve body B on the side of an actuator such as a cylinder, a second port 2 connected to a tank or a fluid source via a switching valve (not shown), and a pilot port 3 for guiding pilot pressure. And a valve housing portion 4 communicating with these ports, and a first valve body 5 and a second valve body 6 are incorporated in the valve housing portion 4.
1 shows a state where communication between the first port 1 and the second port 2 is cut off, FIG. 2 shows a control flow state from the first port 1 to the second port 2, and FIG. 3 shows a second port. A free flow state from 2 to the first port 1 is shown.

The valve body B includes a first member 1 that forms the first port 1, the valve storage portion 4, and a communication passage 8 that communicates the first port 1, a second member b 2 that forms the second port 2 and the valve storage portion 4. And the third member b3 in which the pilot port 3 and the pilot chamber 7 are formed.
The first member b1 is formed with a spring chamber 9 for accommodating a spring member 16 to be described later, and the pilot chamber 7 of the third member b3 is accommodated in the valve by the pilot pressure introduced to the pilot port 3. A pilot piston 10 that moves toward the portion 4 is provided.

  Further, a first seat portion 11 that is inclined with respect to the axial center of the valve housing portion 4 is formed at an end portion of the second member b2 on the first port 1 side, and the first seat portion 11 is formed as a first valve body. The poppet part 5a is opened and closed. The first valve body 5 is composed of the poppet portion 5a and a cylindrical portion 5b which is slidably supported on the inner wall of the valve storage portion 4 and is provided on the second port side from the poppet portion 5a. A through-hole 12 penetrating in the axial direction is provided. The cylindrical portion 5b is formed with a concave portion 5c extending in the axial direction on the outer wall thereof, and a throttle hole 13 communicating the concave portion 5c with the through hole 12. The aperture 13 is formed so as to be positioned closer to the second port than the first sheet 11 when the first sheet 11 is closed.

Further, a second seat portion 14 that is inclined toward the axial center of the through hole 12 is formed on the end face of the first valve body 5 on the first port 1 side, and the second seat portion 14 is connected to the second valve body. 6 poppet parts 6a are opened and closed.
A rod member 15 that passes through the through hole 12 of the first valve body 5 and faces the pilot piston 10 is connected to the poppet portion 6 a of the second valve body 6. The rod member 15 includes a sliding portion 15 a that is slidably supported by the through hole 12. A small diameter portion having an outer diameter smaller than the inner diameter of the through hole 12 is provided on the second valve body 6 side. 15b is formed. The small diameter portion 15b forms a fluid passage when the second sheet portion 14 is opened.
Here, the rod member 15 is integrated with the second valve body 6, but the rod member 15 and the second valve body 6 may be separated.

On the other hand, on the first port side of the second valve body 6, a columnar support portion 6c that forms a step 6b between the poppet portion 6a and the support portion 6c is provided in the spring chamber 9, and A coil-shaped spring member 16 is provided on the outer periphery of the support portion 6 c, and both ends of the spring member 16 are received by the step portion 6 b and the inner wall of the spring chamber 9. The spring member 16 exhibits an elastic force that presses the second valve body 6 toward the second seat portion 14.
In the figure, reference numeral 17 denotes a seal member.

The operation of the above slow return device will be described below.
FIG. 1 shows a state in which a tank is connected to the second port 2, the load pressure of the actuator acts on the first port 1, and the pressure on the first port 1 side is higher than the pressure on the second port 2 side. . At this time, the pressure on the first port 1 side acts on the first valve body 5 as shown by the arrow a in the figure, and the poppet portion 5 a closes the first seat portion 11.
The pressure on the first port 1 side also acts on the second valve body 6 as indicated by the arrow b, and the poppet portion 6a closes the second seat portion 14. At this time, since the elastic force of the spring member 16 also acts on the second valve body 6 in the direction in which the second seat portion 14 is closed, the second seat portion 14 is reliably closed.
Thus, since both the 1st sheet | seat part 11 and the 2nd sheet | seat part 14 close, communication with the 1st port 1 and the 2nd port 2 is interrupted | blocked, and the state of an actuator is hold | maintained.
Even if the spring member 16 is not provided, the second valve body 6 closes the second seat portion 14 when the pressure on the first port 1 side acts, but the second seat is caused by the elastic force of the spring member 16. The part is more reliably closed.

  In the control flow state in which the fluid on the actuator side is gradually returned to the tank from the state of FIG. 1, the operator operates the switching valve (not shown) to operate the pilot port with the second port 2 communicating with the tank. Lead pilot pressure to 3 The pilot pressure acts on the pilot piston 10 as indicated by an arrow c in FIG. With this pilot pressure, the pilot piston 10 moves in the direction of the arrow c, and the second valve body 6 is moved via the rod member 15. Thereby, the 2nd sheet | seat part 14 opens.

  At this time, since the pressure on the first port 1 side is higher than the pressure on the second port 2 side, the first valve body 5 closes the first seat portion 11 by this pressure action. Accordingly, the first port 1 communicates with the second port via the communication path 8, the second sheet portion 14, the outer periphery of the small diameter portion 15b of the rod member, the throttle hole 13, and the recess 5c, and the fluid flows as indicated by an arrow. . That is, the flow from the first port 1 to the second port 2 is a control flow in which the flow rate is controlled by passing through the throttle hole 13.

As described above, when the pilot pressure is introduced into the pilot chamber 7, a passage through the throttle hole 13 is formed between the first port 1 and the second port 2 by opening the second seat portion. Unlike the conventional example, there is no need to adjust the opening of the aperture manually.
Since the throttle hole 13 is formed in the first valve body 5 in advance, the opening degree thereof is constant, and even if the throttle is manually formed as in the conventional example, the pilot pressure can even be guided. As a result, a control flow with a predetermined throttle can be made stably.

  On the other hand, the case where the second port 2 is connected to a fluid supply source and hydraulic fluid is supplied to the actuator from the state of FIG. 1 will be described. At this time, since the pressure on the second port 2 side becomes higher than the pressure on the first port 1 side, the first valve body 5 collides with the first member b1 toward the first port 1 side by this pressure action. Until the first sheet portion 11 is opened as shown in FIG. Thus, when the 1st valve body 5 moves to the direction which opens the 1st seat part 11, the 1st valve body 5 pushes the 2nd valve body 6, both move integrally, and 2nd The state which closed the sheet | seat part 14 is maintained.

As described above, when the first seat portion 11 is opened, the second port is connected to the first port 1 via the recess 5 c formed on the outer periphery of the first valve body 5, the first seat portion 11, and the communication passage 8. Communicate. And the opening of the said 1st sheet | seat part 11 is sufficiently large, can make the free flow shown by the arrow of FIG. 3 from the 2nd port to the 1st port 1, and can supply a working fluid to an actuator.
In the state of FIG. 3, the pressure on the second port 2 side acts on the pilot piston 10 as indicated by an arrow d, and the pilot piston 10 moves in a direction away from the rod member 15.

  Further, the elastic force of the spring member 16 acts on the second valve body 6 and the poppet portion 6a is pressed against the second seat portion 14, but when the first valve body 5 moves by pressure action, Since the second seat part 14 is closed and the second valve body 6 is pushed, the spring member 16 may be omitted. However, when the elastic force of the spring member 16 acts, the followability of the second valve body 6 to the first valve body 5 can be improved. For example, even when the position of the first valve body 5 fluctuates due to a pressure change, both can be moved integrally while the second seat portion 14 is closed.

  In the slow return device of the above embodiment, it is not necessary to move the valve body directly by manual operation or to control the throttle, unlike the device of the conventional example. In particular, it is not necessary to manually adjust the throttle opening during the control flow, and the passage through the throttle hole 13 having a predetermined opening can be reliably and easily reproduced, so that the control is stable.

It is sectional drawing of the slow return apparatus of embodiment, and is a figure which shows the state by which the communication between a 1st port and a 2nd port was interrupted | blocked. It is sectional drawing of the slow return apparatus of embodiment, and is a figure which shows the control flow state from a 1st port to a 2nd port. It is sectional drawing of the slow return apparatus of embodiment, and is a figure which shows the free flow state from a 2nd port to a 1st port. It is sectional drawing of the principal part of the conventional slow return apparatus.

Explanation of symbols

B Valve bodies b1 to b3 First to third members 1 First port 2 Second port 3 Pilot port 4 Valve housing portion 5 First valve body 5a Poppet portion 6 Second valve body 6a Poppet portion 7 Pilot chamber 10 Pilot piston 11 1st sheet part 14 2nd sheet part 15 Rod member

Claims (2)

  A valve body, a valve housing portion bored in the valve body, a first port that is bored on one end side of the valve housing portion and communicated with the actuator side, and a fluid source or tank bored in the valve housing portion A first port that opens and closes by a first valve body that moves in an opening direction due to fluid pressure from the second port, and is formed on the inner wall of the valve housing portion. A part of the first valve body is provided with a second seat portion that is opened and closed by the second valve body, and a through hole in which a rod member linked to the second valve body is movably interposed in the first valve body. And the end of the rod member protrudes into the pilot chamber formed at the other end of the valve housing, and is opposed to the pilot piston movably disposed in the pilot chamber. When the second valve body opens the second seat part, a throttle hole is formed in the first valve body for restricting the flow of fluid flowing from the first port to the second port through the second seat part. When the pilot pressure is guided to the pilot chamber with the tank connected to the second port, the first seat portion is closed by the pressure action, and the pilot acting via the pilot piston and the rod member Due to the pressure, the second valve body opens the second seat part, a control flow from the first port to the second port is generated through the throttle hole, a tank is connected to the second port, and the pilot chamber is connected to the pilot chamber. When the pilot pressure is not guided, the first seat portion and the second seat portion are closed by pressure action, the communication between the first port and the second port is shut off, and the fluid is connected to the second port. When connected to, the first sheet portion is opened by the pressure action, slow return device, characterized in that the free flow through the first sheet portion has a configuration that occurs.   The slow return device according to claim 1, further comprising an elastic member that applies a force in a direction to close the second seat portion to the second valve body.

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