JP2004060834A - Control valve equipment for pipe rupture - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide the control valve equipment for pipe rupture that can prevent an adverse effect on the environment by restraining outflow of hydraulic oil to external of the equipment to the minimum when unloading from the condition where holding the load at the time of pipe rupture. <P>SOLUTION: A poppet valve 5 as a main valve that is arranged to the sliding movement free in a housing 3 and closes and communicates between a cylinder connection room 8 and a pipe connection room 9, a spool valve 6 as a pilot valve that is provided with a pilot passage 15a, 15b connecting a back pressure room 10 with the pipe connection room 9 and works with the pilot pressure (the external signal) from a manual pilot valve 108 and makes the pilot flow in the pilot passage 15a, 15b close and communicate and a emergency drain circuit 40 communicating and closing a cylinder connection room 8 with a drain passage 23 are provided. The emergency drain circuit 40 is composed of a drain passage 41 connecting the cylinder connection room 8 with the drain passage 23 and a manual open-and-close valve 42 for opening and closing the drain passage 41. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a pipe rupture control valve device (hose rupture valve) that is provided in a hydraulic machine such as a hydraulic shovel and prevents a load from dropping when a cylinder hose breaks.
[0002]
[Prior art]
In a hydraulic machine, for example, a hydraulic excavator, it is desired that the load can be prevented from dropping even if a hose or a steel pipe for transporting pressurized oil to a hydraulic cylinder which is an actuator for driving a load such as a boom or an arm is broken. There is a need, and a pipe break control valve device called a hose rupture valve is provided for such a need.
[0003]
As a prior art of a pipe break control valve device, there are, for example, those described in JP-A-11-303810, JP-A-2001-187903, and the like. This pipe break control valve device of the prior art includes a poppet valve body as a main valve that shuts off and communicates between the cylinder connection chamber and the pipe connection chamber, and a valve between the back pressure chamber and the pipe connection chamber of the poppet valve body. It has a structure that has a spool valve element as a pilot valve in the connected pilot passage. During normal operation, the spool valve element as a pilot valve is operated by an external signal (pilot pressure of a manual pilot valve) to operate the main valve. The poppet valve body is opened to allow hydraulic oil to be discharged from the hydraulic cylinder, and when the hydraulic piping breaks, the poppet valve body holds the shut-off position as the main valve and functions as a load check valve, The hydraulic oil is prevented from flowing out of the cylinder, and the load of a boom, an arm or the like can be prevented from dropping.
[0004]
[Problems to be solved by the invention]
However, the above prior art has the following problems.
[0005]
When the hydraulic pipe breaks, the pipe break control valve device holds the load of the boom, the arm and the like as described above, and prevents the fall thereof. At this time, it is dangerous if the load remains raised, so it is necessary to lower the load to a safe position.
[0006]
In the above prior art, when lowering the load from a state where the load is held to a safe position when the hydraulic pipe breaks, the operating lever of the manual pilot valve is operated, and the spool pressure as the pilot valve is operated by the pilot pressure. By opening the poppet valve as a valve, the hydraulic oil in the hydraulic cylinder is discharged little by little, and the load is reduced. However, in this case, since the hydraulic pipe has been broken, the hydraulic oil discharged from the hydraulic cylinder may flow out of the device from the break opening of the hydraulic pipe, which may adversely affect the environment.
For example, when the hydraulic oil is directly discharged from the break of the hydraulic pipe, the hydraulic oil flows down to the surface of the ground and soils the ground. If a container is placed below the break in the hydraulic pipe and hydraulic oil is stored in the container, the leakage of hydraulic oil to the ground can be minimized, but the hydraulic oil stored in the container is then discarded. Have to do so, which can eventually pollute the environment.
[0007]
An object of the present invention is to provide a pipe break control valve device that can minimize the outflow of hydraulic oil to the outside of a device when the load is reduced from a state where the load is held when the pipe breaks, and can prevent adverse effects on the environment. To provide.
[0008]
[Means for Solving the Problems]
(1) In order to achieve the above object, the present invention is provided between a supply / discharge port of the first working chamber and a hydraulic pipe of a double-acting hydraulic cylinder having first and second working chambers, In a pipe break control valve device for controlling a flow rate of pressure oil flowing from the first working chamber to the hydraulic pipe by an external signal, a cylinder connection chamber connected to a supply / discharge port of the first working chamber, A housing provided with a pipe connection chamber to be connected, and a back pressure chamber; and a poppet valve as a main valve slidably disposed in the housing to shut off and communicate between the cylinder connection chamber and the pipe connection chamber. A spool valve as a pilot valve provided in a pilot passage connecting between the body and the back pressure chamber and the pipe connection chamber, and operated by the external signal to shut off and communicate a pilot flow rate flowing through the pilot passage. If, it is assumed and a emergency drain circuit for communicating and blocking the drain passage provided in the cylinder connecting chamber connected to the supply and discharge port of the first working chamber housing.
[0009]
Accordingly, when the load is lowered from the state held by the pipe break control valve device when the hydraulic pipe breaks, the emergency drain circuit is operated to communicate the cylinder connection chamber with the drain passage provided in the housing, so that the housing The hydraulic oil in the first working chamber of the hydraulic cylinder can be returned to the tank by using the existing drain passage provided in the hydraulic cylinder, whereby the hydraulic cylinder can move and reduce the load. Also, at this time, the hydraulic oil in the first working chamber of the hydraulic cylinder is returned to the tank, so that it is possible to minimize the outflow of the hydraulic oil to the outside of the device and to prevent adverse effects on the environment.
[0010]
(2) In order to achieve the above object, the present invention provides a double-acting hydraulic cylinder having first and second working chambers provided between a supply / discharge port of the first working chamber and a hydraulic pipe. A pipe connection control valve device for controlling a flow rate of pressure oil flowing from the first working chamber to the hydraulic pipe by an external signal, wherein a cylinder connection chamber connected to a supply / discharge port of the first working chamber; A housing provided with a pipe connection chamber connected to the pipe, and a back pressure chamber; and a main valve slidably disposed in the housing, for shutting off and communicating between the cylinder connection chamber and the pipe connection chamber. A pilot valve, which is provided in a pilot passage connecting between the back pressure chamber and the pipe connection chamber, is operated by the external signal, and serves as a pilot valve for shutting off and communicating a pilot flow rate flowing through the pilot passage. A valve body, an emergency bypass circuit for communicating and shutting off a supply / discharge port of the first working chamber and a supply / discharge port of the second working chamber, and the communication between the emergency bypass circuit and the first working chamber. A drain circuit that recirculates an excess flow of the pressure oil flowing into the second working chamber to the tank.
[0011]
Thus, when the load is lowered from the state held by the pipe break control valve device when the hydraulic pipe breaks, the emergency bypass circuit is operated to supply / discharge the supply / discharge port of the first working chamber and the supply / discharge of the second working chamber of the hydraulic cylinder. By communicating with the port, the hydraulic oil flows from the first working chamber to the second working chamber, and the excess flow rate of the working oil returns to the tank via the drain circuit, and the hydraulic cylinder moves to reduce the load. it can. Also, at this time, part of the hydraulic oil in the first working chamber of the hydraulic cylinder flows into the second working chamber, and the rest flows back to the tank. It is possible to prevent adverse effects.
[0012]
When the entire amount of hydraulic oil flowing out of the first working chamber of the hydraulic cylinder is returned to the tank, high-pressure hydraulic oil may flow through a drain hose connecting a drain circuit to the tank. Must-have. In the present invention, the hydraulic oil flowing through the drain circuit is a part of the hydraulic oil flowing out of the first working chamber, and the flow rate of the hydraulic oil flowing through the drain circuit is small. Therefore, the pressure of the drain hose connecting the drain circuit to the tank is reduced. it can.
[0013]
(3) In (2) above, preferably, the emergency bypass circuit connects and disconnects the bypass passage connecting the supply / discharge port of the first working chamber and the supply / discharge port of the second working chamber. A first valve means, wherein the drain circuit connects a supply / discharge port of the second working chamber to a drain passage provided in the housing; a second valve means for opening and closing the drain passage; Having.
[0014]
Thus, the emergency bypass circuit communicates and shuts off the supply / discharge port of the first working chamber of the hydraulic cylinder and the supply / discharge port of the second working chamber, and the drain circuit connects the first working chamber when the emergency bypass circuit communicates. Then, the excess flow rate of the pressure oil flowing into the second working chamber is returned to the tank.
[0015]
(4) In the above (3), the first and second valve means are, for example, manual switching valves.
[0016]
This eliminates the need to provide a hydraulic circuit for the signal circuit as operating means for the first and second valve means, thereby simplifying the area around the housing of the pipe break control valve device.
[0017]
(5) In the above (3), the first and second valve means are preferably electromagnetic switching valves.
[0018]
This eliminates the need to provide a hydraulic circuit for the signal circuit as operating means for the first and second valve means, thereby simplifying the area around the housing of the pipe break control valve device.
[0019]
In addition, the operation of the solenoid-operated directional control valve is facilitated because the load can be lowered by operating the switch only by operating the switch.
[0020]
Further, by arranging the switch of the electromagnetic switching valve in a safe place for work, the work can be performed safely without directly touching the housing of the pipe break control valve device.
[0021]
(6) In the above (2), preferably, the pipe break control valve device includes a control valve for controlling a flow of pressure oil supplied to the hydraulic cylinder, and a manual pilot valve for switching the control valve. A bypass passage provided in the hydraulic drive device, wherein the emergency bypass circuit connects a supply / discharge port of the first working chamber to a supply / discharge port of the second working chamber; and valve means for opening and closing the bypass passage. Wherein the valve means is a hydraulic pilot switching valve, and the pilot pressure generated by the manual pilot valve is introduced to the spool valve body as the external signal to the spool valve body. And a selection valve for selectively guiding the valve means.
[0022]
By adjusting the operation amount of the manual pilot valve, the opening area of the valve means as the hydraulic pilot switching valve can be adjusted, and the flow rate flowing out of the first working chamber of the hydraulic cylinder can be adjusted arbitrarily. Can safely lower the load.
[0023]
In addition, by installing the selection valve in a safe place for work, the work can be performed safely without directly touching the housing of the pipe break control valve device.
[0024]
(7) In the above (2), preferably, the pipe break control valve device includes a control valve for controlling a flow of pressure oil supplied to the hydraulic cylinder, a manual pilot valve for switching the control valve, The emergency bypass circuit is connected to a supply / discharge port of the first working chamber and a supply / discharge port of the second working chamber. The hydraulic drive device includes a pilot primary pressure circuit that generates a predetermined pilot primary pressure. And a valve means for opening and closing the bypass passage, and the valve means is a hydraulic pilot switching valve, and guides the pilot pressure generated by the manual pilot valve to the spool valve body as the external signal. A first position for interrupting communication between the pilot primary pressure circuit and valve means serving as the hydraulic pilot switching valve; And a selector valve that shuts off communication between the valve and the spool valve body and switches to a second position for guiding a predetermined pilot primary pressure of the pilot primary pressure circuit to valve means as the hydraulic pilot switching valve. Shall be.
[0025]
Thus, by installing the selection valve in a safe place for work, the work can be performed safely without directly touching the housing of the pipe break control valve device.
[0026]
(8) In the above (7), preferably, there is further provided a means for reducing a predetermined pilot primary pressure of the pilot primary pressure circuit guided to valve means as the hydraulic pilot switching valve and guiding the pilot primary pressure to the pressure receiving chamber of the control valve. Prepare.
[0027]
By operating the selection valve only to the second position, the valve means as the hydraulic pilot switching valve is operated to open the bypass passage, and the reduced pilot primary pressure acts on the pressure receiving chamber of the control valve to slightly operate the control valve. Since a drain circuit for operating and returning the excess flow rate to the tank is formed, the load can be reduced by a simple operation.
[0028]
(9) In the above (2), preferably, the emergency bypass circuit connects a supply / discharge port of the first working chamber to a supply / discharge port of the second working chamber, Valve means for opening and closing, a relief valve is provided on a pipe connecting the cylinder connection chamber and the tank, and a pressure generating means is provided downstream of the relief valve, and the pressure generated by the pressure generating means is A first pressure receiving chamber in which a predetermined pilot pressure is applied in a valve opening direction to the relief valve, and a first operation of the hydraulic cylinder; A second pressure receiving chamber to which the load pressure of the chamber is applied in the valve opening direction, and a poppet that communicates and shuts off the cylinder connection chamber and the tank are opened and closed according to the load pressure of the first working chamber. And Shall comprise a changing means for changing the magnitude of the pilot pressure applied to said first pressure receiving chamber, and an operating means for operating said valve means and changing means.
[0029]
As a result, during normal operation, if an excessive external force acts on the hydraulic cylinder and the load pressure is going to become excessive, the relief valve operates and the spool valve body as a pilot valve is opened by the pressure generated by the pressure generating means, and the main valve is opened. By opening the poppet valve body as a valve, the relief valve provided in the actuator line is operated, and it is possible to prevent the generation of excessive load pressure.
[0030]
On the other hand, when lowering the boom to a safe position when the pipe is broken, the operating means is operated to reduce the magnitude of the pilot pressure applied to the first pressure receiving chamber by the changing means, thereby setting the spring pressure of the relief valve. When the load pressure rises and an excessive external force acts on the hydraulic cylinder and the load pressure becomes excessive, the poppet of the relief valve is kept closed, and the pressure oil of the hydraulic cylinder is disconnected from the broken pipe (actuator line). Is prevented from flowing out to the user.
[0031]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[0032]
FIG. 1 is a diagram showing a pipe break control valve device according to a first embodiment of the present invention in a hydraulic circuit.
[0033]
In FIG. 1, reference numeral 100 denotes a pipe break control valve that constitutes a pipe break control valve device of the present embodiment. The pipe break control valve 100 is driven by a hydraulic pump 101 and pressure oil discharged from the hydraulic pump 101. A hydraulic actuator (hydraulic cylinder) 102, a control valve 103 for controlling the flow of pressure oil supplied from the hydraulic pump 101 to the hydraulic cylinder 102, actuator lines 105 and 106 as hydraulic piping extending from the control valve 103, It is connected to actuator lines 105 and 106 and is provided in a hydraulic drive device having main overload relief valves 107 a and 107 b for limiting the maximum pressure in the circuit, a manual pilot valve 108, and a tank 109.
[0034]
In the present embodiment, the hydraulic drive device is mounted on, for example, a hydraulic shovel, and the hydraulic cylinder 102 is, for example, a boom cylinder that drives a boom of the hydraulic shovel. The hydraulic actuator 102 is a double-acting hydraulic cylinder having two working chambers, a bottom chamber 102a and a rod chamber 102b.
[0035]
The pipe break control valve 100 has a housing 3 having two input / output ports 1 and 2, and the input / output port 1 is directly attached to a first supply / discharge port 102 c that opens to a bottom chamber 102 a of the hydraulic cylinder 102. The input / output port 2 is connected via an actuator line 105 to one of the two actuator ports 103a, 103b 103a of the control valve 103. The other actuator port 103b is connected via an actuator line 106 to a second supply / discharge port 102d opening to the rod side chamber 102b of the hydraulic cylinder 102.
[0036]
In the housing 3, a poppet valve element 5 as a main valve, a spool valve element 6 as a pilot valve that operates by a pilot pressure from a manual pilot valve 108 as an external signal to operate the poppet valve element 5, an overload A small relief valve 7 having the function of a relief valve is provided. The spool valve element 6 also serves as a spool valve element as an auxiliary valve for controlling a flow rate in a small flow rate area (described later).
[0037]
In the housing 3, a cylinder connection chamber 8 connected to the input / output port 1, a pipe connection chamber 9 connected to the input / output port 2, and a back pressure chamber 10 are provided, and a poppet valve body 5 as a main valve is provided. Receives the pressure of the back pressure chamber 10 on the back side, shuts off and communicates between the cylinder connection chamber 8 and the pipe connection chamber 9, and is slidably disposed in the housing 3 so as to change the opening area according to the amount of movement. Have been. The poppet valve element 5 has an opening area that is increased according to the amount of movement of the poppet element element 5 and controls the amount of pilot flow that flows from the cylinder connection chamber 8 to the back pressure chamber 10 according to the opening area. A feed hack slit 11 is provided as a variable throttle passage. A spring 13 for holding the poppet valve element 5 at the illustrated blocking position is provided in the back pressure chamber 10.
[0038]
Pilot passages 15a and 15b are formed in the housing 3, and the back pressure chamber 10 and the pipe connection chamber 9 are connected via the pilot passage 15a, the spool valve element 6, and the pilot passage 15b. The pilot passage 15b also serves as a part (described later) of a sub passage of the auxiliary valve.
[0039]
The spool valve element 6 has a pilot variable throttle section 6a that can communicate with the pilot passages 15a and 15b. A spring for setting the initial valve opening force of the pilot variable throttle section 6a is provided at the operating end of the spool valve element 6 in the valve closing direction. A pressure receiving chamber 17 is provided at the operating end of the spool valve element 6 in the valve opening direction. The pressure receiving chamber 17 is provided with the pilot pressure as the external signal through a pilot line 32. The pilot pressure is guided to the pressure receiving chamber 17. The amount of movement of the spool valve element 6 is determined by the control force by the (external signal) and the urging force of the spring 16, and the opening area of the pilot variable throttle 6a changes according to this amount of movement, and the pilot passages 15a and 15b Shut off and control the flowing pilot flow. The end of the spool valve body where the spring 16 is disposed is connected to a tank 109 via a drain passage 21 and a drain hose 22 in order to make the movement of the spool valve body 6 smooth.
[0040]
A sub passage 15c is formed in the housing 3, and the cylinder connection chamber 8 and the pipe connection chamber 9 are connected via the sub passage 15c, the spool valve element 6, and the pilot passage 15b. The spool valve element 6 also serves as a spool valve element as an auxiliary valve for controlling a flow rate in a small flow rate range. For this reason, the spool valve element 6 includes a sub variable restrictor 50a that can communicate the sub passage 15c and the pilot passage 15b. Further, the opening area of the sub variable throttle portion 50a changes according to the amount of movement of the spool valve element 6, and the sub flow rate flowing through the sub passage 15c and the pilot passage 15b is cut off and controlled.
[0041]
In the housing 3, a relief passage 15e located on the entrance side of the small relief valve 7 and a drain passage 15f located on the exit side are provided. The relief passage 15e is connected to the cylinder connection chamber 8, and the drain passage 15f Is connected to the tank 109 via a drain passage 23 and a drain hose 22. A throttle 34 as pressure generating means is provided in the drain passage 15f. From the small relief valve 7 and the throttle 34, the pressure generated by the throttle 34 is applied to the spool valve body 6 at the same level as the pilot pressure as an external signal. A signal passage 36 leading to a pressure receiving chamber 35 acting as a side driving force is branched.
[0042]
FIG. 2 shows the relationship between the opening area of the poppet valve element 5 and the opening area of the feedback slit 11 with respect to the movement amount (stroke) of the poppet valve element 5. When the poppet valve element 5 is in the shut-off position, the feedback slit 11 has a predetermined initial opening area A. ₀ The poppet valve element 5 starts to open from the shut-off position, and the opening area of the poppet valve element 5 and the feedback slit 11 increases proportionally as the moving amount increases. Feedback slit 11 has initial opening area A ₀ , The poppet valve element 5 can function as a check valve (described later).
[0043]
FIG. 3 shows the relationship between the flow rate of the pilot variable throttle portion 6a of the spool valve element 6 (the pilot flow rate) and the flow rate of the poppet valve element 5 (the main flow rate) with respect to the pilot pressure from the manual pilot valve 108 which is an external signal. The relationship between these and the passing flow rate (sub-flow rate) of the sub-variable throttle portion 50a of the spool valve element 6 and the relationship between these and the total passing flow rate of the pipe break control valve 100 will be described. In the figure, X1 is a characteristic line of the flow control of the pilot variable restrictor 6a, X2 is a characteristic line of the flow control of the poppet valve element 5, X3 is a characteristic line of the flow control of the sub variable restrictor 50a, and X4 is the sum of them. This is a characteristic line of flow control, that is, a characteristic line of flow control of the pipe break control valve 100.
[0044]
In FIG. 3, the pilot pressure is 0 to P ₂ The range up to is the dead zone of the pilot variable throttle section 6a of the spool valve element 6, and during this time, the pilot variable throttle section 6a is in the shut-off state. Pilot pressure is P ₂ , The pilot variable throttle portion 6a of the spool valve element 6 starts to open as shown by the characteristic line X1, and the pilot pressure becomes P ₂ , The opening area of the pilot variable throttle section 6a increases, and accordingly, the flow rate of the pilot variable throttle section 6a, that is, the pilot flow rate flowing through the pilot passages 15a and 15b also increases.
[0045]
Also, if the pilot pressure is P ₃ (> P ₂ ) Is the dead zone of the poppet valve element 5 until the pilot flow rate reaches the predetermined flow rate. During this period, even if the pilot flow rate occurs, the pressure drop in the back pressure chamber 10 due to the feedback slit 11 is insufficient, and the poppet valve element 5 is kept in the shut-off position by the initial setting force of the spring 13. Pilot pressure is P ₃ When the pilot flow reaches a predetermined flow rate, the poppet valve element 5 starts to open as indicated by the characteristic line X2, and the pilot pressure becomes P ₃ , The opening area of the poppet valve element 5 increases, and accordingly, the flow rate of the poppet valve element, that is, the main flow rate, also increases.
[0046]
Further, when the pilot pressure is 0 to P ₁ The range up to is the dead zone of the sub-variable restrictor 50a of the spool valve element 6, and during this time, the sub-variable restrictor 50a is in the shut-off state. Pilot pressure is P ₁ , The sub-variable throttle portion 50a of the spool valve element 6 starts to open as indicated by the characteristic line X3, and the pilot pressure becomes P ₁ , The opening area of the sub-variable throttle unit 50a increases, and accordingly, the passing flow rate of the sub-variable throttle unit 50a, that is, the sub-flow rate flowing through the sub passage 15c and the pilot passage 15b also increases.
[0047]
Also, P ₁ <P ₂ The opening timing is set so that the sub-variable restrictor 50a of the spool valve element 6 opens earlier than the pilot variable restrictor 6a, and the sub-variable restrictor 50a is provided with a flow control function in the fine operation area. I have.
[0048]
As described above, the passing flow rate of the pilot variable throttle portion 6a of the spool valve element 6, the poppet valve element 5, and the sub variable throttle section 50a of the spool valve element 6 change, and as a result, the total passing flow rate of the pipe break control valve 100 becomes a characteristic line. It changes as indicated by X4.
[0049]
Returning to FIG. 1, an emergency drain circuit 40 is provided in the housing 3 for communicating and blocking the cylinder connection chamber 8 connected to the supply / discharge port 102 c of the bottom chamber 102 a of the hydraulic cylinder 102 and the drain passage 23. The drain circuit 40 includes a drain passage 41 that connects the cylinder connection chamber 8 and the drain passage 23, and a manual opening / closing valve 42 that opens and closes the drain passage 41. The manual opening / closing valve 42 is a valve whose maximum opening area is set small so that the boom can be slowly lowered when the pipe is broken, and is, for example, a needle valve.
[0050]
Next, the operation of the pipe breakage control valve device configured as described above will be described.
[0051]
First, a normal operation in which the actuator line 105 is not broken will be described.
[0052]
1) When supplying pressure oil to the bottom side of the hydraulic cylinder 102
When the operation lever of the manual pilot valve 108 is operated in the direction A in the figure and the control valve 103 is switched to the position on the left side in the figure, the pressure oil of the hydraulic pump 101 is supplied via the control valve 103 to the pipe connection chamber 9 of the pipe break control valve 100. And the pressure in the pipe connection chamber 9 rises. At this time, the pressure in the cylinder connection chamber 8 of the pipe break control valve 100 is the load pressure on the bottom side of the hydraulic cylinder 102, and the feedback slit 11 has the initial opening area A as described above. ₀ Therefore, the pressure in the back pressure chamber 10 is also the load pressure, and while the pressure in the pipe connection chamber 9 is lower than the load pressure, the poppet valve body 5 is kept in the shut-off position. When the pressure in the chamber 9 becomes higher than the load pressure, the poppet valve element 5 immediately moves upward in the drawing, and the pressure oil can flow into the cylinder connection chamber 8, and the pressure oil of the hydraulic pump 101 is supplied to the bottom side of the hydraulic cylinder 102. Is done. Pressure oil from the rod side of the hydraulic cylinder 102 is discharged to the tank 109 via the control valve 103.
[0053]
2) When pressure oil is discharged from the bottom side of the hydraulic cylinder 102 to the control valve 103
When the operation lever of the manual pilot valve 108 is operated in the direction B in the figure and the control valve 103 is switched to the right side in the figure, the pressure oil of the hydraulic pump 101 is supplied to the rod side of the hydraulic cylinder 102 via the control valve 103. . At the same time, the pilot pressure from the manual pilot valve 108 is guided to the pressure receiving chamber 17 of the spool valve element 6, the spool valve element 6 is moved by the pilot pressure, and the pilot variable throttle portion 6a of the spool valve element 6 The opening area is commensurate with. Therefore, a pilot flow according to the pilot pressure flows through the pilot passages 15a and 15b, and the poppet valve element 5 is opened and the movement amount is controlled according to the pilot flow. When the spool valve element 6 is moved by the pilot pressure, the sub-variable restrictor 50a is opened prior to the pilot variable restrictor 6a, and a sub-flow rate according to the pilot pressure flows through the sub passage 15c and the pilot passage 15b. For this reason, the pressure oil on the bottom side of the hydraulic cylinder 102 is discharged to the control valve 103 while being controlled by the pilot variable throttle portion 6a and the sub variable throttle portion 50a of the poppet valve element 5 and the spool valve element 6 of the pipe break control valve 100. , And further discharged to the tank 109.
[0054]
3) Holding the load pressure on the bottom side of the hydraulic cylinder 102
When the load pressure on the bottom side of the hydraulic cylinder 102 is high, such as when the suspended load is held at the neutral position of the control valve 103, the poppet valve element 5 in the shut-off position is similar to the conventional load check valve. A function (load check function) of maintaining the load pressure and reducing the amount of leakage.
[0055]
4) When excessive external force acts on the hydraulic cylinder 102
When an excessive external force acts on the hydraulic cylinder 102 and the pressure in the cylinder connection chamber 8 becomes high, the pressure in the relief passage 15e increases, the small relief valve 7 opens, and pressure oil flows into the drain passage 15f provided with the throttle 34. As a result, the pressure in the signal path 36 increases, the spool valve element 6 moves to open the pilot variable throttle section 6a, and the pilot flow rate flows through the pilot paths 15a and 15b. As a result, the poppet valve element 5 is also opened, and high-pressure oil generated by external force is discharged to the tank 109 by the overload relief valve 107a connected to the actuator line 105, thereby preventing damage to the device.
[0056]
5) When piping breaks
If the actuator line 105 breaks, the poppet valve element 5 at the shut-off position functions as a load check valve (holding valve) as in the case of holding the suspended load, and the pressure on the bottom side of the hydraulic cylinder 102 is reduced. Prevents oil from spilling and prevents the boom from falling.
[0057]
6) When lowering the load (boom) when the pipe breaks
When lowering the boom to a safe position when the pipe is broken, the operator manually opens the manual opening / closing valve 42 of the emergency drain circuit 40 and sends the hydraulic oil in the bottom chamber 102 a of the hydraulic cylinder 102 to the drain passage 41 and the drain passage 23. , And return to the tank 109 via the drain hose 22. Thereby, the hydraulic oil in the bottom side chamber 102a of the hydraulic cylinder 102 can be discharged little by little while controlling the flow rate, and the boom can be lowered slowly.
[0058]
According to the present embodiment configured as described above, the following effects can be obtained.
[0059]
1. By merely providing the poppet valve element 5 in the flow path through which the entire amount of the pressure oil supplied to and discharged from the hydraulic cylinder 102 passes, the various functions of the check valve, the load check valve, and the overload relief valve for supplying the pressure oil can be performed. Therefore, a valve device with small pressure loss can be configured, and efficient operation with small energy loss can be performed.
[0060]
2. Since the pipe break control valve 100 can be miniaturized as compared with the conventional one, the chance of breakage in operation decreases and the degree of freedom in design increases. Furthermore, since the number of parts is small, the frequency of failure is reduced, reliability can be improved, and manufacturing can be performed at low cost.
[0061]
3. When the high pressure oil generated by an excessive external force acts on the small relief valve 7 to open the poppet valve element 5 and open the main overload relief valve 107a to the tank, the pressure passing through the small relief valve 7 Since the oil has a small flow rate, the same function as the conventional overload relief valve can be realized by the small small relief valve 7. Moreover, since the pressure oil released from the small relief valve 7 to the tank is made through the drain passage 21 equivalent to the conventional drain line, the drain break control valve 100 does not require a drain pipe dedicated to the overload relief valve. In addition, the piping around the piping break control valve 100 can be simplified.
[0062]
4. A sub-variable throttle unit 50a is added to the spool valve body 6, the sub-variable throttle unit 50a controls the flow rate in the fine operation area, and the pilot variable throttle unit 6a controls the poppet valve body 5; The opening timing of the poppet valve element 5 can be set irrespective of the flow rate control. Even if the flow rate control characteristic in the fine operation area is changed, the entire flow rate control width does not change, and the operability in the fine operation area is improved. Therefore, a smooth flow control characteristic can be obtained even when the slope of the characteristic line of the flow control is reduced.
[0063]
For example, in FIG. 3, when the characteristic line of the sub-variable throttle portion 50a of the spool valve element 6 is a broken line X5, even if this is changed to X3 of the present embodiment so that the inclination becomes smaller, the poppet valve P of opening timing of body 5 ₃ Since the point does not change, the flow control characteristic of the poppet valve element 5 does not change, and the characteristic of the total passing flow rate of the pipe break control valve 100 changes from X6 to X4. That is, although the flow control characteristics in the fine operation region change, the change in the maximum flow passing through the pipe break control valve 100 is slight, and the entire flow control width hardly changes. Further, the opening timing of the sub-variable throttle portion 50a of the spool valve element 6 is set to ₁ The same applies to the case of shifting from the point, and the opening timing of the poppet valve element 5 is P ₃ It does not change from the point, and the whole flow control width hardly changes.
[0064]
Conversely, even if the flow control characteristic of the poppet valve element 5 is changed by changing the characteristics (the inclination of the characteristic line X and the opening timing) of the pilot variable throttle section 6a of the spool valve element 6, the sub-variable The flow control characteristic in the fine operation region by the throttle unit 50a does not change.
[0065]
5. Further, a wide range of flow control characteristics can be set by arbitrarily combining the change of the characteristics of the sub variable throttle portion 50a of the spool valve body 6 and the change of the characteristics of the pilot variable throttle portion 6a (change of the characteristics of the poppet valve body 5). And the degree of freedom in design increases, so that the present invention can be applied to various types of actuators (hydraulic cylinders) having different required flow rate control characteristics.
[0066]
6. Since the emergency drain circuit 40 is provided, when lowering the boom after the pipe is broken, the hydraulic oil in the bottom chamber 102a of the hydraulic cylinder 102 is used to make use of the drain passage 23 and the drain hose 22 originally provided in the pipe break control valve 100. To return to the tank 109, so that the operation lever of the manual pilot valve 108 is finely operated in the direction B in the drawing to open the pilot variable throttle section 6a and the poppet valve body 5 to discharge the hydraulic oil in the bottom side chamber 102a of the hydraulic cylinder 102. As compared to the case where the hydraulic oil is used, it is possible to minimize the leakage of the hydraulic oil to the outside of the device, and it is possible to prevent the adverse effect on the environment.
[0067]
7. Since the maximum opening area of the manual opening / closing valve 42 of the emergency drain circuit 40 is set small, even if the manual opening / closing valve 42 is fully opened, the flow rate flowing through the drain passage 41 is suppressed to a minute flow rate, and the boom is slowly lowered. be able to. For this reason, the operation of the operator becomes easy, and the boom can be lowered safely and reliably.
[0068]
A second embodiment of the present invention will be described with reference to FIG. In the figure, the same components as those shown in FIG. 1 are denoted by the same reference numerals.
[0069]
In FIG. 4, 100A is a pipe break control valve that constitutes a pipe break control valve device according to the present embodiment. The pipe break control valve 100A has a bottom side chamber 102a, which is two working chambers of the hydraulic cylinder 102, and a rod 100A. The emergency bypass circuit 60 that communicates and shuts off the side chamber 102b and the rod side chamber 102b of the hydraulic cylinder 102 communicates and shuts off with the drain passage 23. When the emergency bypass circuit 60 communicates, the emergency bypass circuit 60 An emergency drain circuit 40 </ b> A that recirculates an excess flow of the pressure oil flowing into the side chamber 102 b to the tank 109 is provided. The emergency bypass circuit 60 includes a bypass passage 61 that connects a supply / discharge port 102c of the bottom chamber 102a of the hydraulic cylinder 102 and a supply / discharge port 102d of the rod-side chamber 102b, and a manual opening / closing valve 62 that opens and closes the bypass passage 61. The emergency drain circuit 40A includes a drain passage 41A that connects the supply / discharge port 102d of the rod side chamber 102b of the hydraulic cylinder 102 to the drain passage 23, and a manual opening / closing valve 42A that opens and closes the drain passage 41A. ing. The manual opening / closing valve 62 is, for example, a needle valve having a small maximum opening area so that the boom can be slowly lowered when the pipe is broken. Similarly, the manual on-off valve 42A is also a needle valve, for example, in which the maximum opening area is set small.
[0070]
In the present embodiment configured as above, 1) when supplying pressure oil to the bottom side of the hydraulic cylinder 102, 2) when discharging pressure oil from the bottom side of the hydraulic cylinder 102 to the control valve 103, 3). When the load pressure on the bottom side of the hydraulic cylinder 102 is maintained, 4) when an excessive external force acts on the hydraulic cylinder 102, and 5) the operation when the pipe is broken is the same as the operation of the first embodiment. .
[0071]
When the pipe is broken, when lowering the boom to a safe position, the operator first manually opens the manual open / close valve 42A of the emergency drain circuit 40A, and then manually opens the manual open / close valve 62 of the emergency bypass circuit 60, The hydraulic fluid in the bottom chamber 102a of the hydraulic cylinder 102 is guided to the rod chamber 102b, and the excess flow of the area difference between the bottom chamber 102a and the rod chamber 102b of the hydraulic cylinder 102 among the amount of oil flowing out of the bottom chamber 102a is drained. It returns to the tank 109 via 41A, the drain passage 23, and the drain hose 22. Thereby, the hydraulic oil in the bottom side chamber 102a of the hydraulic cylinder 102 can be discharged little by little while controlling the flow rate, and the boom can be lowered slowly.
[0072]
According to the present embodiment configured as described above, the effects 1 to 5 and the effects 6 and 7 described in the first embodiment can be obtained. That is, when the boom is lowered after the pipe is broken, it is possible to minimize the flow of the hydraulic oil to the outside of the device, and to prevent adverse effects on the environment. Further, the operation at that time can be facilitated, and the boom can be safely and securely lowered.
[0073]
In the first embodiment, the entire amount of the hydraulic oil flowing out of the bottom chamber 102a of the hydraulic cylinder 102 is returned to the tank 109 via the drain passage 23 and the drain hose 22. There is a possibility of flowing, and it is necessary to increase the pressure of the drain hose 22 to some extent. However, in the present embodiment, not the entire amount of oil flowing out from the bottom side chamber 102a of the hydraulic cylinder 102 but a part of the oil amount is returned to the tank 109 via the drain passage 23 and the drain hose 22, so that high pressure is applied to the drain hose 22. Is less likely to damage the drain hose 22 even when the hydraulic oil flows, and the existing low-pressure drain hose can be used as it is.
[0074]
Further, in the first embodiment, since the hydraulic cylinder 102 is contracted without returning the hydraulic oil to the rod-side chamber 102b of the hydraulic cylinder 102, air may enter the rod-side chamber 102b of the hydraulic cylinder 102, Although it is necessary to bleed air, in this embodiment, since air does not enter the rod side chamber 102b of the hydraulic cylinder 102, subsequent handling becomes easy.
[0075]
Furthermore, since it is not necessary to add a hydraulic pipe of a signal circuit outside the pipe break control valve as in the embodiments described below (fourth and fifth embodiments), the area around the housing of the pipe break control valve 100A is not required. Can be simplified.
[0076]
A third embodiment of the present invention will be described with reference to FIG. In the figure, components that are the same as those shown in FIGS. 1 and 4 are given the same reference numerals.
[0077]
In FIG. 5, reference numeral 100B denotes a pipe break control valve constituting a main part of the pipe break control valve device according to the present embodiment. The pipe break control valve 100B is a bottom side chamber which is two working chambers of the hydraulic cylinder 102. An emergency bypass circuit 60A for communicating and blocking between the rod side chamber 102b and the rod side chamber 102b, and a communication and blocking between the rod side chamber 102b and the drain passage 23 of the hydraulic cylinder 102, and the bottom side chamber of the hydraulic cylinder 102 when communicating with the emergency bypass circuit 60A. An emergency drain circuit 40 </ b> B that recirculates an excess flow of the pressure oil flowing from the 102 a into the rod side chamber 102 b to the tank 109 is provided. The emergency bypass circuit 60A includes a bypass passage 61 that connects a supply / discharge port 102c of the bottom chamber 102a of the hydraulic cylinder 102 and a supply / discharge port 102d of the rod-side chamber 102b, and a proportional solenoid valve 62A that opens and closes the bypass passage 61. The emergency drain circuit 40B includes a drain passage 41A that connects the supply / discharge port 102d of the rod side chamber 102b of the hydraulic cylinder 102 and the drain passage 23, and a proportional solenoid valve 42B that opens and closes the drain passage 41A. ing. The proportional solenoid valve 62A is a valve having a small maximum opening area so that the boom can be slowly lowered when the pipe is broken, and the proportional solenoid valve 42B is also a valve having a small maximum opening area.
[0078]
Further, the pipe breakage control valve device of the present embodiment has a power supply 65, a switch 66, and signal lines 67, 67a, 67b as operating means of the proportional solenoid valves 62A, 42B, and the signal lines 67a, 67b are proportional electromagnetic valves. The valves 62A, 42B are connected to solenoids 62a, 42a.
[0079]
The operation of the present embodiment configured as described above is based on the fact that the manual on-off valves 62 and 42A are replaced with the proportional solenoid valves 62A and 42B, and the switch 66 is turned on instead of manually operating the manual on-off valves 62 and 42A. It is the same as the second embodiment shown in FIG. That is, when lowering the boom to a safe position when the pipe is broken, when the operator turns on the switch 66, the proportional solenoid valves 62A and 42B are opened, and the hydraulic oil in the bottom side chamber 102a of the hydraulic cylinder 102 is opened as in the first embodiment. Is guided to the rod side chamber 102b, and the excess flow rate of the area difference is returned to the tank 109 via the drain passage 41A, the drain passage 23, and the drain hose 22, whereby the hydraulic oil in the bottom side chamber 102a of the hydraulic cylinder 102 is gradually reduced. Drain and allow the boom to lower slowly.
[0080]
Therefore, also according to the present embodiment, when lowering the boom after the pipe breaks, it is possible to minimize the flow of the hydraulic oil to the outside of the device, prevent the environment from being adversely affected, and reduce the operation at that time. The same effects as in the second embodiment can be obtained, for example, the boom can be easily and safely and securely lowered.
[0081]
In addition, according to the present embodiment, the proportional solenoid valves 62A and 42B operate and the boom can be lowered simply by operating the switch 66, so that the operation is further facilitated.
[0082]
Further, by arranging the switch 66 in a safe place for work, the work can be performed safely without directly touching the pipe break control valve 100B and without approaching the pipe break control valve 100B or the load boom. .
[0083]
A fourth embodiment of the present invention will be described with reference to FIG. In the figure, components that are the same as those shown in FIGS. 1 and 4 are given the same reference numerals.
[0084]
In FIG. 6, reference numeral 100C denotes a pipe break control valve constituting a main part of the pipe break control valve device according to the present embodiment. This pipe break control valve 100C is a bottom side chamber which is two working chambers of the hydraulic cylinder 102. An emergency bypass circuit 60B is provided for connecting and disconnecting the rod 102a and the rod-side chamber 102b.
[0085]
Further, the pipe breakage control valve device of the present embodiment includes a manual switching circuit 70 for switching the destination of the pilot pressure, which is an external signal, between the spool valve element 6 and the emergency bypass circuit 60B.
[0086]
The emergency bypass circuit 60B includes a bypass passage 61 connecting a supply / discharge port 102c of the bottom chamber 102a of the hydraulic cylinder 102 and a supply / discharge port 102d of the rod side chamber 102b, and a spool valve as valve means for opening and closing the bypass passage 61. And a body 62B. The spool valve body 62B has a variable throttle portion 62b, and the maximum opening area thereof is set small so that the boom can be slowly lowered when the pipe is broken. The spool valve body 62B is a hydraulic pilot switching valve having a pressure receiving chamber 62c, and is normally held at a closed position shown in the figure.
[0087]
The manual switching circuit 70 has a manual switching valve 71 provided between the pilot line 32a and the pilot line 32b. The pilot pressure from the manual pilot valve 108 is supplied to the spool valve body between the pilot line 32a and the pilot line 32b. A pilot line 32 leading to the pressure receiving chamber 17 is formed. Further, a pilot line 72 branches from the manual switching valve 71, and the pilot line 72 is connected to a pressure receiving chamber 62c of the spool valve body 62B. The manual switching valve 71 connects the pilot line 32a to the pilot line 32b, connects the pilot line from the manual pilot valve 108 to the pressure receiving chamber 17 of the spool valve body 6, and connects the pilot line 32a to the pilot line 71. And a second position for guiding the pilot pressure to the pressure receiving chamber 62d of the spool valve body 62B, and can be switched between the first position and the second position by the operation lever 71a.
[0088]
In the present embodiment configured as described above, during normal operation, the manual switching valve 71 is switched to the illustrated first position, whereby the pilot line 32a communicates with the pilot line 32b. The normal operation can be performed in the same manner as described above.
[0089]
When lowering the boom to a safe position when the pipe is broken, the operator first operates the operation lever 71a of the manual switching valve 71 to switch the manual switching valve 71 from the first position shown to the second position, and then to operate the manual pilot valve The operation lever 108 is operated in the B direction in the figure. At this time, the operation lever is gradually operated within the range of the fine operation or the half operation. As a result, the control valve 103 is switched to the intermediate position between the neutral position and the right position in the drawing, and the actuator line 106 is partially connected to each of the hydraulic pump 101 and the tank 109 via the throttle.
That is, a drain circuit is formed in which the excess flow rate of the pressure oil flowing into the rod side chamber 102b from the bottom side chamber 102a of the hydraulic cylinder 102 is returned to the tank 109 when the emergency bypass circuit 60B communicates.
[0090]
Further, since the pilot line 32a communicates with the pilot line 72, the pilot pressure from the manual pilot valve 108 is guided to the pressure receiving chamber 62c of the spool valve body 62B via the manual switching valve 71, the pilot line 32a, and the pilot line 72. The spool valve body 62B is switched from the illustrated closed position to a position where the variable throttle portion 62b is located. At this time, the opening degree of the variable throttle portion 62b of the spool valve body 62B has an opening area corresponding to the pilot pressure from the manual pilot valve 108 (the operation amount of the operation lever of the manual pilot valve 108). Thereby, the hydraulic oil in the bottom side chamber 102a of the hydraulic cylinder 102 is guided to the rod side chamber 102b, and the surplus flow rate of the area difference is returned to the tank 109 via the actuator line 106 and the control valve 103, and the bottom side chamber of the hydraulic cylinder 102 is The hydraulic oil of 102a can be discharged little by little while controlling the flow rate, and the boom can be lowered slowly.
[0091]
Therefore, also according to the present embodiment, when lowering the boom after the pipe breaks, it is possible to minimize the flow of the hydraulic oil to the outside of the device, prevent the environment from being adversely affected, and reduce the operation at that time. The same effects as in the second embodiment can be obtained, for example, the boom can be easily and safely and securely lowered.
[0092]
Further, according to the present embodiment, by adjusting the operation amount of the operation lever of the manual pilot valve 108, the opening area of the variable throttle portion 62b of the spool valve body 62B can be adjusted, and the flow rate flowing out of the bottom side chamber 102a can be reduced. Since it can be adjusted arbitrarily, the boom can be safely lowered at any speed.
[0093]
Further, by installing the manual switching valve 71 in a safe place for the work, it is possible to work safely without directly touching the pipe break control valve 100C and without approaching the pipe break control valve 100C or the load boom. Can be performed.
[0094]
A fifth embodiment of the present invention will be described with reference to FIG. In the figure, the same reference numerals are given to the same components as those shown in FIGS. 1, 4 and 5.
[0095]
7, reference numeral 100C denotes a pipe break control valve constituting a main part of the pipe break control valve device according to the present embodiment. The pipe break control valve 100C is a bottom side chamber which is two working chambers of the hydraulic cylinder 102. An emergency bypass circuit 60B for communicating and shutting off the communication between the rod 102a and the rod side chamber 102b, communication and cutoff of the pilot pressure from the manual pilot valve 108, which is an external signal, and cutoff and communication of the pilot primary pressure of the pilot primary pressure generating circuit 75. And an electromagnetic switching circuit 70A for switching.
[0096]
The emergency bypass circuit 60B is the same as that of the fourth embodiment shown in FIG.
[0097]
The pilot primary pressure circuit 75 sets the pilot pump 76 and the discharge pressure of the pilot pump 76 to a predetermined value (for example, 50 kg / cm). ² ), And pilot lines 78 and 79 for outputting the discharge pressure as a signal pressure. The pilot line 78 is connected to the discharge path of the pilot pump 76, and the pilot line 79 is connected to the pressure receiving chamber 62c of the spool valve body 62B. The pilot primary pressure circuit 75 is normally provided in a hydraulic drive device of a hydraulic machine such as a hydraulic shovel or the like as a hydraulic source for an operation system such as a manual pilot valve 108. For example, the discharge pressure of a pilot pump 76 is set via a pilot line 80. It is led to a manual pilot valve 108.
[0098]
The electromagnetic switching circuit 70A includes an electromagnetic switching valve 71A installed between the pilot lines 32a and 32b constituting the pilot line 32 and between the pilot lines 78 and 79, an electromagnetic switching valve 120 installed on the pilot line 110, It has a power supply 85, a switch 86, and signal lines 87 and 87a provided as operating means for the electromagnetic switching valve 71A and the electromagnetic switching valve 120. The signal line 87 is connected to the solenoid 71a of the electromagnetic switching valve 71A, and the signal line 87a Is connected to the solenoid 120a of the electromagnetic switching valve 120.
[0099]
The electromagnetic switching valve 71A connects the pilot line 32a with the pilot line 32b, disconnects the pilot line 78 from the pilot line 79, disconnects the pilot line 32a from the pilot line 32b, and disconnects the pilot line 32a from the pilot line 32b. 78 and a second position 71c for communicating the pilot line 79. When the solenoid 71a is excited, the first position 71b is switched to the second position 71c.
[0100]
The electromagnetic switching valve 120 has a first position 120b having a large opening area for communicating the pilot line 110 and a second position 120c having a throttle 120d. When the solenoid 120a is excited, the first position 120b changes from the first position 120b to the second position 120b. The position is switched to the two positions 120c.
[0101]
The pilot line 81a branches off from the pilot line 79, the pilot line 81b is connected to the pilot line 110, and the pilot line 110 is connected to the pressure receiving chamber 103b of the control valve 103. The pressure receiving chamber 103b is a pressure receiving chamber in which the pilot pressure when the operation lever of the manual pilot valve 108 is operated in the direction B in the drawing is guided through the pilot line 110. The pilot line 81a is provided with a throttle 82, a pressure receiving chamber 103b, and a check valve 83 for preventing the flow of pressure oil from the pilot line 110 side to the pilot line 79 side.
[0102]
Assuming that the aperture area of the aperture 82 is A1 and the aperture area of the aperture 120d is A2, A1 <A2 is set.
[0103]
In the present embodiment configured as above, during normal operation, the switch 86 is opened, the solenoids 71a, 120a are de-energized, and the electromagnetic switching valves 71A, 120 are switched to the illustrated first positions 71b, 120b. , The pilot line 32a and the pilot line 32b communicate with each other, the communication between the pilot line 78 and the pilot line 79 is cut off, and the pilot line 110 is in a communicating state. At this time, the electromagnetic switching valve 120 is also at the first position 120b, and the pilot pressure generated when the operation lever of the manual pilot valve 108 is operated in the direction B in the drawing is guided to the pressure receiving chamber 103b of the control valve 103. Is blocked by the check valve 83 and is not guided to the pilot line 79. Therefore, the normal operation can be performed similarly to the above embodiment.
[0104]
When lowering the boom to a safe position when the pipe breaks, the operator turns on the switch 86, excites the solenoids 71a and 120a, switches the electromagnetic switching valve 71A from the illustrated first position 71b to the second position 71c, The switching valve 120 is switched to the second position 120c having the throttle 120d. As a result, the communication between the pilot line 32a and the pilot line 32b is cut off, and the pilot line 78 and the pilot line 79 communicate with each other. Therefore, the pilot primary pressure of the pilot primary pressure circuit 76 is controlled by the spool valve The spool valve element 62B is guided to the pressure receiving chamber 62c of 62B, and is switched from the illustrated closed position to the position where the variable throttle portion 62b is located.
[0105]
At this time, since the manual pilot valve 108 is not operated, the output port of the pilot valve 108 communicates with the tank port, and the pilot line 110 communicates with the tank 109 via the pilot valve 108. Therefore, a flow of pressurized oil from the pilot line 79 to the tank 109 via the throttle 82, the pilot line 81, the throttle 120 d at the second position 120 c of the electromagnetic switching valve 120, the pilot line 110, and the pilot valve 108 occurs. Is reduced by the throttle 82 and the throttle 120 d at the second position 120 c of the electromagnetic switching valve 120, and a small pressure intermediate between the pilot primary pressure and the tank pressure is applied downstream of the throttle 82 of the pilot line 81. Side, and this is guided to the pressure receiving chamber 103b of the control valve 103 as a control pressure. As a result, the control valve 103 is finely operated and switched to the intermediate position between the illustrated neutral position and the illustrated right position, and the actuator line 106 is partially connected to each of the hydraulic pump 101 and the tank 109 via a throttle. State. That is, a drain circuit is formed in which the excess flow rate of the pressure oil flowing into the rod side chamber 102b from the bottom side chamber 102a of the hydraulic cylinder 102 is returned to the tank 109 when the emergency bypass circuit 60B communicates.
[0106]
Thereby, the hydraulic oil in the bottom side chamber 102a of the hydraulic cylinder 102 is guided to the rod side chamber 102b, and the surplus flow rate of the area difference is returned to the tank 109 via the actuator line 106 and the control valve 103, and the bottom side chamber of the hydraulic cylinder 102 is The hydraulic oil of 102a can be discharged little by little, and the boom can be lowered slowly.
[0107]
Therefore, also according to the present embodiment, when lowering the boom after the pipe breaks, it is possible to minimize the flow of the hydraulic oil to the outside of the device, prevent the environment from being adversely affected, and reduce the operation at that time. The same effects as in the second embodiment can be obtained, for example, the boom can be easily and safely and securely lowered.
[0108]
Further, according to the present embodiment, the spool valve body 62B is switched to the open position only by operating the switch 86, and the reduced pilot pressure acts on the pressure receiving chamber 103b of the control valve 103 to cause the control valve 103 to operate. Since a drain circuit for finely operating and returning the surplus flow rate to the tank is formed, the boom can be lowered by a simple operation, and the operation is further facilitated.
[0109]
Further, by arranging the switch 86 in a safe place for work, the work can be performed safely without directly touching the pipe break control valve 100C and without approaching the pipe break control valve 100C or the load boom. .
[0110]
A sixth embodiment of the present invention will be described with reference to FIG. In the figure, the same reference numerals are given to members equivalent to those shown in FIG. 7 in the fifth embodiment described above.
[0111]
In FIG. 8, reference numeral 100D denotes a pipe break control valve constituting a main part of a pipe break control valve device according to the present embodiment. This pipe break control valve 100D uses a poppet type relief valve 200 that can change its set pressure by a pilot signal instead of the relief valve 7 used in the fifth embodiment described above. The relief valve 200 is connected to a poppet 200 e, a pressure receiving chamber 200 a to which pilot pressure is applied, a pressure receiving chamber 200 b to which the load pressure of the bottom chamber 102 a of the hydraulic cylinder 102 is led, and a bottom chamber 102 a of the hydraulic cylinder 102. A cylinder connection chamber 200c, a tank-side chamber 200f connected to the tank 109 via the throttle 34, and a spring 200d for setting a set pressure are provided.
[0112]
An electromagnetic switching valve 201 is provided on a pipe connecting the pressure receiving chamber 200a of the relief valve 200 and the pilot pump 76, and the set pressure of the relief valve 200 is changed by switching the valve position of the electromagnetic switching valve 201. Is done. Further, an electromagnetic switching valve 62C is provided on a pipe connecting the bottom chamber 102a and the rod chamber 102b of the hydraulic cylinder 102 to communicate and shut off the pipe. A switch 86a for switching the valve positions of these electromagnetic switching valves 201 and 62C is provided.
[0113]
In the present embodiment configured as described above, during normal operation, the switch 86a is opened and the solenoids 201a and 62d are de-energized. The electromagnetic switching valve 62C is at the illustrated closed position 62e, the electromagnetic switching valve 201 is at the illustrated first position 201b, and the pilot receiving pressure is applied to the pressure receiving chamber 200a of the relief valve 200. In this state, the load pressure in the bottom chamber 102a of the hydraulic cylinder 102 becomes relatively high, and the load pressure is guided to the pressure receiving chamber 200b of the relief valve 200, and the pressing force of the poppet 200e by the load pressure and the pilot primary pressure is reduced. When the sum exceeds the pressing force of the spring 200d, the cylinder connection chamber 200c and the tank side chamber 200f communicate with each other, and guide the pressure oil in the bottom side chamber 102a of the hydraulic cylinder 102 to the tank 109.
[0114]
Here, the set pressure of the spring 200d is reduced by the pressing force due to the pilot primary pressure of the pressure receiving chamber 200a, and the reduced set pressure becomes a value equivalent to the set pressure of the small relief valve 7 shown in FIG. It is set as follows. Thus, the normal operation can be performed as in the fifth embodiment.
[0115]
When the boom is lowered to a safe position when the pipe is broken, the switch 86a is closed, the solenoid 201a of the electromagnetic switching valve 201 and the solenoid 62d of the electromagnetic switching valve 62C are excited, and the valve positions are switched to the second positions 201c and 62f, respectively. . Thereby, the pressure receiving chamber 200a of the relief valve 200 is connected to the tank 109, the pressure receiving chamber 200a becomes substantially equal to the tank pressure, and the set pressure in the opening direction of the poppet 200e becomes higher than the setting in the normal operation. On the other hand, the bottom chamber 102a and the rod chamber 102b of the hydraulic cylinder 102 are connected via a throttle 62g at a second position 62f of the electromagnetic switching valve 62C. In this state, when the manual pilot valve 108 is finely operated in the direction B, the control valve 103 is switched to the intermediate position between the illustrated neutral position and the right position, and the actuator line 106 is partially connected to the hydraulic pump 101 and the tank 109 respectively. It is in a state of being connected via a diaphragm. Therefore, similarly to the fifth embodiment described above, a drain circuit is formed to return the excess flow of the pressure oil flowing from the bottom chamber 102a of the hydraulic cylinder 102 to the rod chamber 102b to the tank 109.
[0116]
Thereby, the boom can be lowered slowly as in the fifth embodiment.
[0117]
Also, when lowering the boom to a safe position when the pipe breaks, if the set pressure of the relief valve 200 is the same as the setting during normal operation, an excessive external force acts on the hydraulic cylinder 102 and the hydraulic cylinder 102 When the load pressure of the bottom chamber 102a becomes excessive and exceeds the set pressure of the relief valve 200, the poppet 200e of the relief valve 200 opens, and pressure oil flows into the drain passage 15f provided with the throttle 34. As a result, the pressure in the signal passage 36 increases, the spool valve body 6 moves to open the pilot variable throttle section 6a, and the pilot flow rate flows through the pilot passages 15a and 15b, whereby the poppet valve body 5 also opens. The pressure oil in the bottom side chamber 102a of the hydraulic cylinder 102 flows out of the broken portion of the actuator line 105 to the outside.
[0118]
In the present embodiment, when the switch 86a is closed and the electromagnetic switching valve 201 is switched to the second position 201c, the set pressure in the opening direction of the poppet 200e becomes higher than the setting at the time of the normal operation, so that an excessive external force is applied to the hydraulic cylinder 102. The poppet 200e of the relief valve 200 is kept closed even if the load pressure of the bottom chamber 102a of the hydraulic cylinder 102 becomes excessively large. The outflow from the broken portion of the line 105 to the outside is prevented.
[0119]
Therefore, according to the present embodiment, when the boom is lowered after the pipe is broken, it is possible to further reliably prevent the hydraulic oil from flowing out of the device and prevent the environment from being adversely affected. Further, similarly to the above embodiment, the operation can be facilitated, and the boom can be lowered safely and reliably.
[0120]
In the above-described embodiment, the pipe break control valve constituting the main part of the present invention is provided with a variable throttle portion 6a provided on a spool valve body 6 serving as a pilot valve, and a poppet valve body 5 serving as a main valve. A feed hack slit 11 is provided to increase the opening area in accordance with the amount of movement of the valve element 5 and to control the amount of pilot flow that flows from the cylinder connection chamber 8 to the back pressure chamber 10 in accordance with the opening area. The body 6 and the poppet valve body 5 are configured as a variable throttle valve that controls the flow rate according to the pilot pressure (external signal) from the manual pilot valve 108, but the spool valve body as the pilot valve communicates with the pilot line and shuts off. The opening / closing valve may be configured such that the poppet valve body as the main valve is provided with a fixed throttle section and the poppet valve body is used as the opening / closing valve.
[0121]
In the above-described embodiment, the pilot variable throttle unit 6a and the sub variable throttle unit 50a are provided on the spool valve body 6 as a pilot valve. However, only the pilot variable throttle unit 6a may be provided. In this case, the sub variable throttle portion 60a may be omitted together with the sub passage 15c, or the sub variable throttle portion 60 may be formed in a spool valve separate from the spool valve element 6.
[0122]
Further, in the sixth embodiment shown in FIG. 8, the poppet-type relief valve 200 and the electromagnetic switching valve 201 are provided in combination with the electromagnetic switching valve 62C, however, FIGS. 1, 4, 5, and 6 Also, in each of the embodiments shown in FIG. 7, a poppet type relief valve 200 and an electromagnetic switching valve 201 may be provided instead of the small relief valve 7, whereby the same as in the sixth embodiment shown in FIG. The effect of can be obtained.
[0123]
【The invention's effect】
ADVANTAGE OF THE INVENTION According to this invention, when unloading from the state which hold | maintained the load at the time of a break of a hydraulic piping, outflow of hydraulic oil to the exterior of apparatus can be minimized, and it can prevent that it has a bad influence on an environment.
[0124]
According to the present invention, when the load is reduced from the state where the load is held when the hydraulic pipe is broken, the pressurized oil is guided from the first working chamber to the second working chamber, and the excess flow is returned to the tank. The amount of hydraulic oil flowing through the circuit is small, and the pressure of the drain hose connecting the drain circuit to the tank can be reduced.
[0125]
Further, according to the present invention, the periphery of the housing of the pipe break control valve device can be simplified.
[0126]
Further, according to the present invention, the load can be reduced only by operating the switch, so that the operation is facilitated.
[0127]
Further, according to the present invention, by installing the switch and the selection valve in a safe place for operation, the housing of the pipe break control valve apparatus is not directly manipulated, and the pipe break control valve apparatus and the load are approached. And work safely.
[0128]
Further, according to the present invention, even when an excessive external force acts on the hydraulic cylinder and the load pressure becomes excessive, it is possible to prevent the hydraulic oil of the hydraulic cylinder from flowing out of the broken pipe to the outside.
[Brief description of the drawings]
FIG. 1 is a diagram showing a piping break control valve device according to a first embodiment of the present invention together with a hydraulic drive device in which the same is disposed in a hydraulic circuit.
FIG. 2 is a diagram illustrating a relationship between an opening area of a poppet valve body and an opening area of a feedback slit with respect to a movement amount (stroke) of the poppet valve body.
FIG. 3 shows the characteristics of the flow rate of the pilot variable throttle unit (pilot flow rate), the flow rate of the poppet valve element (main flow rate), and the characteristics of the sub variable throttle unit for the pilot pressure of the pipe break control valve device shown in FIG. It is a figure which shows the relationship of the characteristic of the passing flow rate (sub flow rate), and the characteristic of the passing flow rate which added them.
FIG. 4 is a diagram showing a piping break control valve device according to a second embodiment of the present invention together with a hydraulic drive device in which the piping break control valve device is disposed by a hydraulic circuit.
FIG. 5 is a diagram showing a piping breakage control valve device according to a third embodiment of the present invention together with a hydraulic drive device in which it is disposed by a hydraulic circuit.
FIG. 6 is a diagram showing a piping break control valve device according to a fourth embodiment of the present invention together with a hydraulic drive device in which the same is disposed in a hydraulic circuit.
FIG. 7 is a diagram showing a pipe break control valve device according to a fifth embodiment of the present invention together with a hydraulic drive device in which it is disposed by a hydraulic circuit.
FIG. 8 is a diagram showing a piping break control valve device according to a sixth embodiment of the present invention together with a hydraulic drive device in which the device is disposed by a hydraulic circuit.
[Explanation of symbols]
1,2 port
3 Housing
5 Poppet valve
6 Spool valve
6a Pilot throttle
7 Small relief valve
8 Cylinder connection chamber
9 Piping connection room
10 Back pressure chamber
11 Feed pack slit
13 Spring
15a, 15b Pilot passage
15c sub passage
15e relief passage
15f drain passage
16 Spring
17 Pressure receiving chamber
21 Drain passage
32, 32a, 32b Pilot line
34 Aperture
35 Pressure receiving chamber
36 signal path
40 40A, 40B Emergency drain circuit
41, 41A drain passage
42, 42A Manual open / close valve
42B proportional solenoid valve
42a solenoid
50a Sub-variable aperture
60,60A, 60B Emergency bypass circuit
61 Bypass passage
62 Manual on-off valve
62A proportional solenoid valve
62a solenoid
62B spool valve
62b Variable throttle unit
62c pressure receiving chamber
65 power supply
66 switch
67, 67a, 67b signal line
70 Manual switching circuit
70A electromagnetic switching circuit
71 Manual switching valve
71A solenoid switching valve
71a solenoid
72 Pilot line
76 Pilot pump
77 relief valve
78,79 Pilot line
80 Pilot line
81 Pilot line
82 Aperture
83 Check valve
85 Power
86 switch
86a switch
87 signal lines
100, 100A, 100B 100C Piping break control valve
101 Hydraulic pump
102 Hydraulic cylinder
102a Bottom side chamber (first working chamber)
102b Rod side chamber (second working chamber)
102c, 102d Supply / discharge port
103 control valve
105 Actuator line (hydraulic piping)
106 Actuator line
107a, 107b Overload relief valve
108 Manual pilot valve
109 tank
110 Pilot line
120 solenoid switching valve
120d aperture
200 Poppet type relief valve
200a, 200b Pressure receiving chamber
200d spring
200e poppet
201 solenoid switching valve

Claims (9)

A double-acting hydraulic cylinder having first and second working chambers is provided between a supply / discharge port of the first working chamber and a hydraulic pipe, and flows out of the first working chamber to the hydraulic pipe by an external signal. In a pipe break control valve device that controls the flow rate of pressurized oil,
A housing provided with a cylinder connection chamber connected to the supply / discharge port of the first working chamber, a pipe connection chamber connected to the hydraulic pipe, and a back pressure chamber;
A poppet valve body as a main valve that is slidably disposed in the housing and that shuts off and communicates between the cylinder connection chamber and the pipe connection chamber;
A spool valve body provided as a pilot valve that is provided in a pilot passage connecting between the back pressure chamber and the pipe connection chamber, and is operated by the external signal to shut off and communicate a pilot flow rate flowing through the pilot passage.
A pipe break control valve device, comprising: an emergency drain circuit that communicates and shuts off a cylinder connection chamber connected to a supply / discharge port of the first working chamber and a drain passage provided in the housing. A double-acting hydraulic cylinder having first and second working chambers is provided between a supply / discharge port of the first working chamber and a hydraulic pipe, and flows out of the first working chamber to the hydraulic pipe by an external signal. In a pipe break control valve device that controls the flow rate of pressurized oil,
A housing provided with a cylinder connection chamber connected to the supply / discharge port of the first working chamber, a pipe connection chamber connected to the hydraulic pipe, and a back pressure chamber;
A poppet valve body as a main valve that is slidably disposed in the housing and that shuts off and communicates between the cylinder connection chamber and the pipe connection chamber;
A spool valve body provided as a pilot valve that is provided in a pilot passage connecting between the back pressure chamber and the pipe connection chamber, and is operated by the external signal to shut off and communicate a pilot flow rate flowing through the pilot passage.
An emergency bypass circuit that connects and disconnects the supply / discharge port of the first working chamber and the supply / discharge port of the second working chamber;
A pipe break control valve device, comprising: a drain circuit that recirculates an excess flow rate of pressure oil flowing from the first working chamber into the second working chamber to a tank when the emergency bypass circuit communicates. The pipe break control valve device according to claim 2,
The emergency bypass circuit has a bypass passage connecting the supply / discharge port of the first working chamber and the supply / discharge port of the second working chamber, and first valve means for opening and closing the bypass passage.
A pipe rupture, wherein the drain circuit has a drain passage connecting a supply / discharge port of the second working chamber and a drain passage provided in the housing, and second valve means for opening and closing the drain passage. Control valve device. The pipe break control valve device according to claim 3,
The pipe break control valve device, wherein the first and second valve means are manual switching valves. The pipe break control valve device according to claim 3,
The pipe break control valve device, wherein the first and second valve means are electromagnetic switching valves. The pipe break control valve device according to claim 2,
The pipe break control valve device is provided in a hydraulic drive device including a control valve that controls the flow of pressure oil supplied to the hydraulic cylinder, and a manual pilot valve that switches the control valve.
The emergency bypass circuit has a bypass passage connecting the supply / discharge port of the first working chamber and the supply / discharge port of the second working chamber, and valve means for opening and closing the bypass passage. Hydraulic pilot switching valve
It further comprises a selection valve for selectively guiding a pilot pressure generated by the manual pilot valve to the spool valve body as the external signal to the spool valve body, and selectively guiding the same pilot pressure to valve means as the hydraulic pilot switching valve. A pipe break control valve device characterized by the above-mentioned. The pipe break control valve device according to claim 2,
The pipe rupture control valve device includes a control valve for controlling a flow of pressure oil supplied to the hydraulic cylinder, a manual pilot valve for switching the control valve, and a pilot primary pressure circuit for generating a predetermined pilot primary pressure. Provided in the hydraulic drive device having
The emergency bypass circuit has a bypass passage connecting the supply / discharge port of the first working chamber and the supply / discharge port of the second working chamber, and valve means for opening and closing the bypass passage. Hydraulic pilot switching valve
A first position for guiding a pilot pressure generated by the manual pilot valve as the external signal to the spool valve body to cut off communication between the pilot primary pressure circuit and valve means as the hydraulic pilot switching valve; A valve which shuts off communication between a valve and the spool valve body and switches to a second position for guiding a predetermined pilot primary pressure of the pilot primary pressure circuit to valve means as the hydraulic pilot switching valve. Characteristic piping break control valve device. The pipe break control valve device according to claim 7,
A piping break control valve device, further comprising means for reducing a predetermined pilot primary pressure of the pilot primary pressure circuit guided to valve means as the hydraulic pilot switching valve and guiding the pilot primary pressure to a pressure receiving chamber of the control valve. The pipe break control valve device according to claim 2,
The emergency bypass circuit has a bypass passage connecting a supply / discharge port of the first working chamber and a supply / discharge port of the second working chamber, and valve means for opening and closing the bypass passage.
A relief valve is provided on a pipe connecting the cylinder connection chamber and the tank, and a pressure generating means is provided downstream of the relief valve, and a pressure generated by the pressure generating means is used for the spool valve as the pilot valve. While acting on the same side as the external signal, the relief valve is actuated by a first pressure receiving chamber to which a predetermined pilot pressure is applied in the valve opening direction and a load pressure of the first operating chamber of the hydraulic cylinder in the valve opening direction. A second pressure receiving chamber to be provided, and a poppet that communicates and shuts off the cylinder connection chamber and the tank, so as to open and close according to the load pressure of the first working chamber,
A piping break control valve device, comprising: a changing unit that changes the magnitude of the pilot pressure applied to the first pressure receiving chamber; and an operating unit that operates the valve unit and the changing unit.

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