JP6483516B2 - Hydraulic circuit of hydraulic equipment - Google Patents

Description

  The present invention relates to a hydraulic circuit of a hydraulic device.

  Conventionally, as a hydraulic circuit of a hydraulic device, for example, there is a technique described in Patent Document 1. In the technique disclosed in Patent Document 1, an accumulator is connected to the head side oil passage connected to the head side oil chamber of the hydraulic actuator separately from the hydraulic oil tank during the reduction operation of the hydraulic actuator. Then, the hydraulic oil discharged from the head side oil chamber of the hydraulic actuator is collected by the hydraulic oil tank and accumulated in the accumulator. Thereby, the discharge route of the hydraulic oil discharged from the head side oil chamber of the hydraulic actuator can be increased, the pressure of the hydraulic oil in the head side oil chamber of the hydraulic actuator can be reduced, and the reduction speed of the hydraulic actuator can be increased.

JP 2008-115878 A

However, in the technique described in Patent Document 1, when the amount of hydraulic oil in the accumulator increases, the gas pressure in the accumulator increases, so the flow rate of hydraulic oil into the accumulator decreases. Therefore, the amount of decrease in the hydraulic oil pressure in the head side oil chamber of the hydraulic actuator becomes small, and the reduction speed of the hydraulic actuator may not increase easily.
The present invention has been made paying attention to the above points, and an object of the present invention is to provide a hydraulic circuit of a hydraulic device that can increase the reduction speed of the hydraulic actuator more appropriately.

  In order to solve the above problems, one embodiment of the present invention is connected to a hydraulic pump that discharges hydraulic oil, a hydraulic actuator that performs expansion and contraction operation using hydraulic oil discharged from the hydraulic pump, and a head-side oil chamber of the hydraulic actuator. The head-side oil passage, the rod-side oil passage connected to the rod-side oil chamber of the hydraulic actuator, the hydraulic oil tank for accumulating hydraulic oil, and the hydraulic pump discharge side during the extension operation of the hydraulic actuator. In addition to connecting the head side oil passage, connecting the hydraulic oil tank and the rod side oil passage, and during the reduction operation of the hydraulic actuator, connecting the discharge side of the hydraulic pump and the rod side oil passage, A control valve for connecting the head side oil passage, a hydraulic cylinder for accumulating hydraulic oil, a rod side oil chamber of the hydraulic cylinder, and a head side of the hydraulic actuator A first oil passage connecting the chamber, a second oil passage connecting the head-side oil chamber of the hydraulic cylinder and the head-side oil chamber of the hydraulic actuator, and a head-side oil chamber of the hydraulic cylinder and the hydraulic oil tank are connected. When the hydraulic actuator is extended, the second oil passage is closed, the third oil passage is opened, and when the hydraulic actuator is contracted, the second oil passage is opened. And an oil passage open / close state control unit for closing the oil passage.

Further, the first oil passage and the second oil passage may be pipes branched from the head side oil passage.
Furthermore, the first oil passage and the second oil passage may be separate pipes from the head-side oil passage.
The first oil path may be a pipe branched from the head-side oil path, and the second oil path may be a different line from the head-side oil path.

  Further, the oil passage opening / closing state control unit is installed in the third oil passage, and when the oil pressure in the rod-side oil passage is equal to or lower than a predetermined set pressure, the reverse pilot check valve that is opened, and the second oil A check valve that allows hydraulic fluid to flow from the head side oil passage side to the head side oil chamber side of the hydraulic cylinder, and a second oil passage between the check valve and the head side oil passage, It may be configured to include a pilot check valve that opens when the oil pressure in the rod side oil passage becomes larger than the set pressure.

Moreover, it is good also as a structure provided with the speed increasing valve which flows hydraulic fluid from a rod side oil path to a head side oil path at the time of expansion | extension operation | movement of a hydraulic actuator, and increases the expansion speed of a hydraulic actuator.
Furthermore, the speed increasing valve is installed in a differential oil passage that connects the rod side oil passage and the head side oil passage, and allows the flow of hydraulic oil from the rod side oil passage side to the head side oil passage side. Is installed in the differential oil passage between the check valve for differential oil passage and the check valve for differential oil passage and the rod side oil passage, and when the hydraulic pressure in the head side oil passage exceeds a predetermined set pressure, the valve is opened. And a differential hydraulic path sequence valve.

  According to one aspect of the present invention, the second oil passage is opened and the third oil passage is closed during the reduction operation of the hydraulic actuator. Therefore, the rod-side oil chamber and the head-side oil chamber of the hydraulic cylinder are connected via the first oil passage, the head-side oil passage, and the second oil passage, thereby forming a differential circuit. Therefore, in addition to the amount of hydraulic oil pushed out from the rod side oil chamber of the hydraulic cylinder, a part of the amount of hydraulic oil discharged from the head side oil chamber of the hydraulic actuator also enters the head side oil chamber of the hydraulic cylinder. A part of the amount of hydraulic oil flowing in and discharged from the hydraulic actuator flows into the hydraulic cylinder without resistance. As a result, the pressure of the hydraulic oil in the head side oil chamber of the hydraulic actuator can be quickly reduced. Thereby, the reduction speed of the hydraulic actuator can be increased more appropriately.

1 is a configuration diagram of a hydraulic circuit 100 of a hydraulic device according to a first embodiment. It is a figure showing operation | movement of the hydraulic circuit 100 of hydraulic equipment. It is a figure showing operation | movement of the hydraulic circuit 100 of hydraulic equipment. The first oil passage and the second oil passage, which are the second embodiment of the present invention, are composed of conduits of a system different from the head-side oil passage, and the first oil passage is branched from the second oil passage. It is a block diagram of the hydraulic circuit 101 of hydraulic equipment. It is a block diagram of the hydraulic circuit 102 of the hydraulic equipment which is a modification of 2nd Embodiment, and the 1st oil path and the 2nd oil path each consist of a pipe line of another system from the head side oil path. A hydraulic circuit of a hydraulic device according to a third embodiment of the present invention, in which a first oil passage is a pipe branched from a head side oil passage, and a second oil path is a pipe of a system different from the head side oil passage. FIG.

An embodiment of a hydraulic circuit 100 of a hydraulic device according to the present invention will be described with reference to the drawings.
(First embodiment)
The hydraulic circuit 100 of the hydraulic device according to the first embodiment is a hydraulic circuit that is mounted on a hydraulic crusher (not shown) and opens and closes a crushing arm (not shown) of the hydraulic crusher. The crushing arm opens when the hydraulic actuator 3 (described later) is reduced, and closes when the hydraulic actuator 3 is extended.
In the first embodiment, an example in which a hydraulic crusher is used as the hydraulic device has been described, but other configurations may be employed. For example, it is good also as a structure using hydraulic equipment other than a hydraulic crusher.

(Constitution)
As shown in FIG. 1, a hydraulic circuit 100 of a hydraulic device includes a hydraulic pump 2, a hydraulic actuator 3, a head side oil passage 4, a rod side oil passage 5, a hydraulic oil tank 6, a control valve 7, And a speed increasing valve 8. The hydraulic cylinder 9, the first oil passage 10, the second oil passage 11, the third oil passage 12, and the oil passage opening / closing state control unit 13 are further provided. FIG. 1 shows the state of the hydraulic circuit 100 until the crushing arm begins to clamp the crushing object during the crushing arm closing operation.

The suction side of the hydraulic pump 2 is connected to the hydraulic oil tank 6. The discharge side of the hydraulic pump 2 is connected to either the head side oil passage 4 or the rod side oil passage 5 via the control valve 7. As a result, the hydraulic pump 2 can suck in the working oil accumulated in the working oil tank 6 and discharge the sucked working oil into either the head side oil passage 4 or the rod side oil passage 5. Yes.
The hydraulic actuator 3 includes a cylinder tube 3a, a piston 3d that divides the space in the cylinder tube 3a into a rod-side oil chamber 3b and a head-side oil chamber 3c, and a piston that is connected to the piston 3d and extends outside the cylinder tube 3a. Rod 3e. The rod side oil chamber 3b is a space that accommodates the piston rod 3e in the space divided by the piston 3d, and the head side oil chamber 3c does not accommodate the piston rod 3e in the space divided by the piston 3d. It is space. The diameter of the piston rod 3e is made slightly smaller than the inner diameter of the cylinder tube 3a, that is, the diameter of the piston 3d. The ratio of the diameter of the piston rod 3e to the diameter of the piston 3d is, for example, in the range of 0.7 or more and less than 0.9.

The rod side oil passage 5 is connected to the rod side oil chamber 3b. Thereby, the rod side oil passage 5 can distribute | circulate hydraulic fluid between the rod side oil chambers 3b (for example, supply and discharge | emission of hydraulic fluid are possible). The head side oil passage 4 is connected to the head side oil chamber 3c. Thereby, the hydraulic fluid can flow between the head side oil passage 4 and the head side oil chamber 3c.
Therefore, when the discharge side of the hydraulic pump 2 and the head side oil passage 4 are connected and hydraulic fluid is discharged from the discharge side of the hydraulic pump 2 to the head side oil passage 4, the hydraulic oil in the head side oil passage 4 is discharged. Flows into the head side oil chamber 3c. Then, due to the inflow of the hydraulic oil, the piston rod 3e moves together with the piston 3d to the rod-side oil chamber 3b side, and the hydraulic actuator 3 extends. On the other hand, when the discharge side of the hydraulic pump 2 and the rod-side oil passage 5 are connected and hydraulic fluid is discharged from the discharge side of the hydraulic pump 2 to the rod-side oil passage 5, the hydraulic oil in the rod-side oil passage 5 is discharged. It flows into the rod side oil chamber 3b. Then, due to the inflow of the hydraulic oil, the piston rod 3e moves together with the piston 3d to the head side oil chamber 3c side, and the hydraulic actuator 3 contracts. Thereby, the hydraulic actuator 3 can be expanded and contracted by the hydraulic oil discharged from the hydraulic pump 2.

The hydraulic oil tank 6 is connected to either the head side oil passage 4 or the rod side oil passage 5 via the control valve 7. Thereby, the hydraulic oil tank 6 can collect the hydraulic oil discharged from either the head side oil passage 4 or the rod side oil passage 5. The hydraulic oil tank 6 is connected to the third oil passage 12 and can recover the hydraulic oil discharged from the third oil passage 12.
The control valve 7 connects the discharge side of the hydraulic pump 2 and the head side oil passage 4 during the closing operation of the crushing arm, that is, when the hydraulic actuator 3 is extended, and the hydraulic oil tank 6 and the rod side oil passage 5. And connect. On the other hand, the control valve 7 connects the discharge side of the hydraulic pump 2 and the rod side oil passage 5 during the opening operation of the crushing arm, that is, the reduction operation of the hydraulic actuator 3, and the hydraulic oil tank 6 and the head side oil. Connect to road 4.

The speed increasing valve 8 includes a first sequence valve 8a, a first check valve 8b, a second check valve 8c, and a second sequence valve 8d.
The first sequence valve 8 a is installed in the rod side oil passage 5. The first sequence valve 8a is opened when the hydraulic pressure in the head-side oil passage 4 becomes equal to or higher than a predetermined first set pressure. The first set pressure includes, for example, the hydraulic pressure in the head-side oil passage 4 when the crushing arm starts to clamp the crushing object during the crushing arm closing operation. The first sequence valve 8 a is configured such that the oil pressure in the rod side oil passage 5 between the rod side oil chamber 3 b of the hydraulic actuator 3 and the first sequence valve 8 a is between the first sequence valve 8 a and the control valve 7. Even if the hydraulic pressure in the rod side oil passage 5 becomes larger than the second set pressure, the valve is opened. The second set pressure includes, for example, the hydraulic pressure in the rod-side oil passage 5 when the crushing arm starts to clamp the crushing object during the crushing arm closing operation.

  The first check valve 8b is installed in the fourth oil passage 8e connected to the rod-side oil passage 5 in parallel with the first sequence valve 8a. The first check valve 8b allows the hydraulic oil to flow from the control valve 7 side to the rod side oil chamber 3b side of the hydraulic actuator 3. The second check valve 8c is installed in a differential oil passage 8f that connects the rod-side oil passage 5 and the head-side oil passage 4 between the rod-side oil chamber 3b of the hydraulic actuator 3 and the first sequence valve 8a. Is done. The second check valve 8c allows the hydraulic oil to flow from the rod side oil passage 5 side to the head side oil passage 4 side.

  The second sequence valve 8 d is installed in the differential oil passage 8 f between the second check valve 8 c and the rod side oil passage 5. The second sequence valve 8d is opened when the hydraulic pressure in the head side oil passage 4 becomes equal to or higher than the third set pressure. The third set pressure includes, for example, the hydraulic pressure in the head-side oil passage 4 until the crushing arm starts to clamp the crushing object during the crushing arm closing operation. The third set pressure is a pressure smaller than the first set pressure. Further, the second sequence valve 8d is configured so that the oil pressure in the rod side oil passage 5 between the rod side oil chamber 3b of the hydraulic actuator 3 and the first sequence valve 8a is between the first sequence valve 8a and the control valve 7. Even when the hydraulic pressure in the rod side oil passage 5 becomes larger than the third set pressure, the valve is opened. On the other hand, in the second sequence valve 8d, the oil pressure in the rod-side oil passage 5 between the rod-side oil chamber 3b of the hydraulic actuator 3 and the first sequence valve 8a is between the first sequence valve 8a and the control valve 7. When the sum of the oil pressure in the rod side oil passage 5 and the third set pressure becomes smaller, the valve is closed regardless of the oil pressure in the head side oil passage 4.

  Therefore, when the crushing arm is closed, that is, when the hydraulic actuator 3 is extended, the discharge side of the hydraulic pump 2 and the head side oil passage 4 are connected, and the hydraulic pressure of the head side oil passage 4 is equal to or higher than the third set pressure. However, when the pressure is less than the first set pressure, the second sequence valve 8d is opened while the first sequence valve 8a is in the closed state. Therefore, the rod side oil passage 5 and the head side oil passage 4 are connected via the differential oil passage 8 f, and a differential circuit is configured for the hydraulic actuator 3.

  Therefore, due to the difference between the area on the head side and the area on the rod side of the piston 3d of the hydraulic actuator 3, a force that pushes the piston 3d from the head side oil chamber 3c side to the rod side oil chamber 3b side is generated. While the differential oil in the rod side oil chamber 3 b of the hydraulic actuator 3 is pushed out to the rod side oil passage 5, the hydraulic oil in the rod side oil passage 5, the differential oil passage 8 f, and the head side oil passage 4. Flows into the head side oil chamber 3c of the hydraulic actuator 3, that is, recirculates. Thereby, in addition to the amount of differential oil discharged from the hydraulic pump 2, the amount of hydraulic oil recirculated by the differential circuit also flows into the head-side oil chamber 3 c of the hydraulic actuator 3. Therefore, the extension speed of the hydraulic actuator 3 is increased, and the closing speed of the crushing arm can be increased.

  Further, during the closing operation of the crushing arm, the crushing arm clamps the crushing object, a load is applied to the hydraulic actuator 3, and the hydraulic pressure in the head side oil passage 4 further increases from the state until the crushing arm begins to crush the crushing object. When the pressure is increased and the hydraulic pressure in the head side oil passage 4 becomes equal to or higher than the first set pressure, the first sequence valve 8a is also opened and the rod side oil passage 5 communicates as shown in FIG. And the oil pressure in the rod side oil passage 5 between the rod side oil chamber 3b of the hydraulic actuator 3 and the first sequence valve 8a, and the inside of the rod side oil passage 5 between the first sequence valve 8a and the control valve 7 are shown. The second sequence valve 8d is closed, and the hydraulic oil discharged from the rod side oil chamber 3b to the rod side oil passage 5 enters the hydraulic oil tank 6 via the control valve 7. Discharged.

  On the other hand, when the crushing arm is opened, that is, when the hydraulic actuator 3 is contracted, the discharge side of the hydraulic pump 2 and the rod-side oil passage 5 are connected as shown in FIG. When the oil pressure in the rod side oil passage 5 between the chamber 3b and the first sequence valve 8a and the oil pressure in the rod side oil passage 5 between the first sequence valve 8a and the control valve 7 are the same, The first sequence valve 8 a and the second sequence valve 8 d remain closed, the rod side oil passage 5 and the head side oil passage 4 are shut off, and no differential circuit is configured for the hydraulic actuator 3.

  The hydraulic cylinder 9 includes a cylinder tube 9a, a piston 9d that divides the space in the cylinder tube 9a into a rod-side oil chamber 9b and a head-side oil chamber 9c, and a piston that is connected to the piston 9d and extends outside the cylinder tube 9a. Rod 9e. The rod-side oil chamber 9b is a space that accommodates the piston rod 9e in the space partitioned by the piston 9d, and the head-side oil chamber 9c does not receive the piston rod 9e in the space partitioned by the piston 9d. It is space. The diameter of the piston rod 9e is made slightly smaller than the inner diameter of the cylinder tube 9a, that is, the diameter of the piston 9d. The ratio of the diameter of the piston rod 9e to the diameter of the piston 9d is, for example, in the range of 0.7 or more and less than 0.9.

The first oil passage 10 connects the head side oil passage 4 between the speed increasing valve 8 and the control valve 7 and the rod side oil chamber 9 b of the hydraulic cylinder 9. Thereby, the first oil passage 10 can circulate the hydraulic oil between the head side oil passage 4 (the head side oil chamber 3 c of the hydraulic actuator 3) and the rod side oil chamber 9 b of the hydraulic cylinder 9. .
The second oil passage 11 connects the head side oil passage 4 between the speed increasing valve 8 and the control valve 7 and the head side oil chamber 9 c of the hydraulic cylinder 9. As a result, the second oil passage 11 can circulate hydraulic oil between the head side oil passage 4 (the head side oil chamber 3c of the hydraulic actuator 3) and the head side oil chamber 9c of the hydraulic cylinder 9. .

The third oil passage 12 connects the second oil passage 11 between the head side oil chamber 9c of the hydraulic cylinder 9 and a third check valve 13b (described later) and the hydraulic oil tank 6. As a result, the third oil passage 12 can discharge the hydraulic oil from the head side oil chamber 9 c of the hydraulic cylinder 9 to the hydraulic oil tank 6.
The oil passage opening / closing state control unit 13 includes a reverse pilot check valve 13a, a third check valve 13b, and a pilot check valve 13c.

The reverse pilot check valve 13 a is installed in the third oil passage 12. The reverse pilot check valve 13a is opened when the oil pressure in the rod-side oil passage 5 between the first sequence valve 8a and the control valve 7 falls below a predetermined fourth set pressure. As the fourth set pressure, for example, there is a pressure slightly smaller than the hydraulic pressure in the rod-side oil passage 5 during the opening operation of the crushing arm.
The third check valve 13 b is installed in the second oil passage 11. The third check valve 13b allows the hydraulic oil to flow from the head side oil passage 4 side (the head side oil chamber 3c side of the hydraulic actuator 3) to the head side oil chamber 9c side of the hydraulic cylinder 9.

The pilot check valve 13c is installed in the second oil passage 11 between the third check valve 13b and the head side oil passage 4 (the head side oil chamber 3c of the hydraulic actuator 3). The pilot check valve 13c is opened when the oil pressure in the rod-side oil passage 5 between the first sequence valve 8a and the control valve 7 becomes larger than the fourth set pressure.
Therefore, when the hydraulic pressure in the rod side oil passage 5 becomes larger than the fourth set pressure during the opening operation of the crushing arm, that is, during the reduction operation of the hydraulic actuator 3, the pilot check valve 13c is opened as shown in FIG. The reverse pilot check valve 13a is closed. Accordingly, the second oil passage 11 is opened, the third oil passage 12 is closed, and the rod-side oil chamber 9b and the head-side oil chamber 9c of the hydraulic cylinder 9 are connected to the first oil passage 10 and the head-side oil. The differential circuit is configured by connecting via the path 4 and the second oil path 11. Therefore, due to the difference between the area on the head side of the piston 9d of the hydraulic cylinder 9 and the area on the rod side, a force for pushing the piston 9d from the head side oil chamber 9c side to the rod side oil chamber 9b side is generated. While the differential oil in the rod side oil chamber 9b of the hydraulic cylinder 9 is pushed out to the head side oil passage 4 through the first oil passage 10, the working oil in the head side oil passage 4 and the second oil passage 11 is pushed. Flows into the head side oil chamber 9 c of the hydraulic cylinder 9.

  The amount of hydraulic oil that flows in is greater than the amount of hydraulic oil that is pushed out from the rod-side oil chamber 9 b of the hydraulic cylinder 9. Therefore, in addition to the amount of hydraulic oil pushed out, a part of the amount of hydraulic oil discharged from the head-side oil chamber 3c of the hydraulic actuator 3 also passes through the head-side oil passage 4 and the second oil passage 11. Then, it flows into the head side oil chamber 9 c of the hydraulic cylinder 9. Therefore, a part of the amount of hydraulic fluid discharged from the hydraulic actuator 3 flows into the hydraulic cylinder 9 without resistance. As a result, the pressure of the hydraulic oil in the head side oil chamber 3c of the hydraulic actuator 3 can be quickly reduced. Thereby, the reduction speed of the hydraulic actuator 3 can be increased more appropriately.

  On the other hand, in the oil path open / close state control unit 13, when the crushing arm is closed, that is, when the hydraulic actuator 3 is extended, the hydraulic oil tank 6 and the rod side oil path 5 are connected as shown in FIG. When the oil pressure in the rod side oil passage 5 becomes equal to or lower than the fourth set pressure, the pilot check valve 13c is closed and the reverse pilot check valve 13a is opened. Therefore, the second oil passage 11 is closed, the third oil passage 12 is opened, and the differential circuit is not configured.

(Operation other)
Next, the operation of the hydraulic circuit 100 of the hydraulic device according to the first embodiment will be described.
First, when the closing operation of the crushing arm is performed, that is, when the hydraulic actuator 3 is extended, the control valve 7 connects the discharge side of the hydraulic pump 2 and the head side oil passage 4 as shown in FIG. In addition, the hydraulic oil tank 6 and the rod-side oil passage 5 are connected. Then, hydraulic oil is discharged from the hydraulic pump 2 to the head side oil passage 4, and the hydraulic oil in the head side oil passage 4 is supplied to the head side oil chamber 3 c of the hydraulic actuator 3 by the discharged hydraulic oil. When hydraulic oil is supplied to the head side oil chamber 3c, the piston 3d moves to the rod side oil chamber 3b side of the hydraulic actuator 3, and the piston rod 3e of the hydraulic actuator 3 moves to the rod side oil chamber 3b side. Thereby, the hydraulic actuator 3 performs an extending operation, and the crushing arm performs a closing operation.

  Here, if the hydraulic pressure in the head side oil passage 4 is equal to or higher than the third set pressure, but less than the first set pressure, the second sequence valve 8d is opened while the first sequence valve 8a remains closed. Thus, the rod-side oil passage 5 and the head-side oil passage 4 are connected via a differential oil passage 8f to form a differential circuit. Therefore, in addition to the amount of differential oil discharged from the hydraulic pump 2, the amount of hydraulic oil recirculated by the differential circuit also flows into the head side oil chamber 3 c of the hydraulic actuator 3. Therefore, the extension speed of the hydraulic actuator 3 can be increased, and the closing speed of the crushing arm can be increased.

At that time, the hydraulic fluid flowing in the head side oil passage 4 is also supplied to the rod side oil chamber 9 b of the hydraulic cylinder 9 via the first oil passage 10. Further, the hydraulic oil is discharged from the head side oil chamber 9 c to the second oil passage 11, and the discharged hydraulic oil is discharged to the hydraulic oil tank 6 through the third oil passage 12.
On the other hand, when the opening operation of the crushing arm is performed, that is, when the hydraulic actuator 3 is extended, the control valve 7 connects the discharge side of the hydraulic pump 2 and the rod side oil passage 5 as shown in FIG. At the same time, the hydraulic oil tank 6 and the head side oil passage 4 are connected. Then, the hydraulic oil is discharged from the hydraulic pump 2 to the rod side oil passage 5, and the hydraulic oil in the rod side oil passage 5 is supplied to the rod side oil chamber 3 b of the hydraulic actuator 3 by the discharged hydraulic oil. When hydraulic oil is supplied to the rod side oil chamber 3b, the piston 3d moves to the head side oil chamber 3c side of the hydraulic actuator 3, and the piston rod 3e of the hydraulic actuator 3 moves to the head side oil chamber 3c side. Thereby, the hydraulic actuator 3 performs a contracting operation, and the crushing arm performs an opening operation.

Here, the oil pressure in the rod-side oil passage 5 between the rod-side oil chamber 3 b of the hydraulic actuator 3 and the first sequence valve 8 a and the rod-side oil passage 5 between the first sequence valve 8 a and the control valve 7. When the internal hydraulic pressure becomes the same, the first sequence valve 8a and the second sequence valve 8d remain in the closed state. Therefore, the connection between the rod side oil passage 5 and the head side oil passage 4 is cut off.
At that time, when the oil pressure of the rod side oil passage 5 becomes larger than the fourth set pressure, the pilot check valve 13c is opened, the reverse pilot check valve 13a is closed, and the second oil passage 11 is opened. Thus, the third oil passage 12 is closed. The rod-side oil chamber 9b and the head-side oil chamber 9c of the hydraulic cylinder 9 are connected via the first oil passage 10, the head-side oil passage 4, and the second oil passage 11, thereby forming a differential circuit. The Therefore, in addition to the amount of hydraulic oil pushed out from the rod-side oil chamber 9 b of the hydraulic cylinder 9, a part of the hydraulic oil discharged from the head-side oil chamber 3 c of the hydraulic actuator 3 is also part of the hydraulic cylinder 9. A part of the hydraulic oil that flows into the head side oil chamber 9c and discharged from the hydraulic actuator 3 flows into the hydraulic cylinder 9 without resistance. As a result, the pressure of the hydraulic oil in the head side oil chamber 3c of the hydraulic actuator 3 can be quickly reduced. Thereby, the reduction speed of the hydraulic actuator 3 can be increased more appropriately.
In the first embodiment, the third check valve 13b in FIG. 1 constitutes a check valve. Similarly, the second check valve 8c in FIG. 1 constitutes a differential oil passage check valve. Further, the second sequence valve 8d in FIG. 1 constitutes a differential oil path sequence valve.

(Effect of 1st Embodiment)
The hydraulic circuit 100 of the hydraulic device according to the first embodiment has the following effects.
(1) According to the hydraulic circuit 100 of the hydraulic device according to the first embodiment, the control valve 7 connects the discharge side of the hydraulic pump 2 and the head side oil passage 4 when the hydraulic actuator 3 is extended. The hydraulic oil tank 6 and the rod side oil passage 5 are connected. The control valve 7 connects the discharge side of the hydraulic pump 2 and the rod side oil passage 5 and connects the hydraulic oil tank 6 and the head side oil passage 4 when the hydraulic actuator 3 is contracted. Further, when the hydraulic actuator 3 is extended, the oil passage opening / closing state control unit 13 closes the second oil passage 11 that connects the head side oil chamber 9c of the hydraulic cylinder 9 and the head side oil passage 4 to the closed state. The third oil passage 12 that connects the head-side oil chamber 9c and the hydraulic oil tank 6 is opened. Further, when the hydraulic actuator 3 is contracted, the second oil passage 11 is opened and the third oil passage 12 is closed.

  According to such a configuration, when the hydraulic actuator 3 is contracted, the second oil passage 11 is opened and the third oil passage 12 is closed. Therefore, the rod-side oil chamber 9b and the head-side oil chamber 9c of the hydraulic cylinder 9 are connected via the first oil passage 10, the head-side oil passage 4, and the second oil passage 11, and a differential circuit is configured. Is done. Therefore, in addition to the amount of hydraulic oil pushed out from the rod-side oil chamber 9 b of the hydraulic cylinder 9, a part of the hydraulic oil discharged from the head-side oil chamber 3 c of the hydraulic actuator 3 is also part of the hydraulic cylinder 9. Part of the amount of hydraulic oil flowing into the head side oil chamber 9c and discharged from the hydraulic actuator 3 flows into the hydraulic cylinder 9 without resistance. As a result, the pressure of the hydraulic oil in the head side oil chamber 3c of the hydraulic actuator 3 can be quickly reduced. Thereby, the reduction speed of the hydraulic actuator 3 can be increased more appropriately.

(2) According to the hydraulic circuit 100 of the hydraulic device according to the first embodiment, the first oil passage 10 and the second oil passage 11 are pipes branched from the head-side oil passage 4.
According to such a configuration, since the first oil passage 10 and the second oil passage 11 are branched from the head-side oil passage 4, it is possible to arrange a small number of piping members with a simple layout.

(3) According to the hydraulic circuit 100 of the hydraulic device according to the first embodiment, the oil passage open / close state control unit 13 is installed in the second oil passage 11 and is connected to the head side oil passage 4 side (the head side of the hydraulic actuator 3). A third check valve 13b that allows the flow of hydraulic oil from the oil chamber 3c side to the head side oil chamber 9c side of the hydraulic cylinder 9 and the third oil passage 12, and the oil pressure in the rod side oil passage 5 is When the pressure is equal to or lower than a predetermined fourth set pressure, the reverse pilot check valve 13a that is in the valve open state, and between the third check valve 13b and the head side oil passage 4 (head side oil chamber 3c of the hydraulic actuator 3) A pilot check valve 13c that is installed in the second oil passage 11 and that opens when the oil pressure in the rod-side oil passage 5 becomes larger than the fourth set pressure.
According to such a configuration, the oil passage opening / closing state control unit 13 can be realized with a relatively simple configuration.

(4) According to the hydraulic circuit 100 of the hydraulic device according to the first embodiment, when the hydraulic actuator 3 is extended, the hydraulic oil is caused to flow from the rod side oil passage 5 to the head side oil passage 4 to extend the hydraulic actuator 3. A speed increasing valve 8 for increasing the speed is provided.
According to such a configuration, the differential circuit is configured when the hydraulic actuator 3 is extended. Therefore, in addition to the amount of differential oil discharged from the hydraulic pump 2, the amount of hydraulic oil recirculated by the differential circuit also flows into the head side oil chamber 3 c of the hydraulic actuator 3. Therefore, the extension speed of the hydraulic actuator 3 can be increased, and the closing speed of the crushing arm can be increased.

(5) According to the hydraulic circuit 100 of the hydraulic device according to the first embodiment, the speed increasing valve 8 is installed in the differential oil path 8f that connects the rod side oil path 5 and the head side oil path 4, and the rod Installed in the second check valve 8c allowing the flow of hydraulic oil from the side oil passage 5 side to the head side oil passage 4 side, and in the differential oil passage 8f between the second check valve 8c and the rod side oil passage 5. The second sequence valve 8d is opened when the hydraulic pressure in the head-side oil passage 4 is equal to or higher than a predetermined third set pressure. According to such a configuration, the speed increasing valve 8 is This can be realized with a relatively simple configuration.

(Second Embodiment)
Next, 2nd Embodiment of this invention is described based on drawing. In addition, about the structure similar to 1st Embodiment, the same code | symbol is used and the detail is abbreviate | omitted.
FIG. 4 is a configuration diagram of the hydraulic circuit 101 of the hydraulic device according to the second embodiment of the present invention.
The second embodiment is different from the first embodiment in that the first oil passage 10 and the second oil passage 11 are each composed of a different line from the head-side oil passage 4. In the second embodiment and the third embodiment (described later), the “first oil passage 10” and the “second oil passage 11” are provided so that the portions different from the configuration of the first embodiment are clarified. These are represented as “first oil passage 14” and “second oil passage 15”, respectively.

  Specifically, as shown in FIG. 4, in the second embodiment, the upstream side 15 a of the second oil passage 15 is connected to the head side oil chamber 3 c of the hydraulic actuator 3. The first oil passage 14 is branched from the upstream side 15 a of the second oil passage 15 and connected to the rod-side oil chamber 9 b of the hydraulic cylinder 9. Thereby, the first oil passage 14 can directly flow the hydraulic oil between the head side oil chamber 3 c of the hydraulic actuator 3 and the rod side oil chamber 9 b of the hydraulic cylinder 9.

Further, the downstream side 15 b of the second oil passage 15 is connected to the head side oil chamber 9 c of the hydraulic cylinder 9. As a result, the second oil passage 15 can directly flow hydraulic oil between the head side oil chamber 3 c of the hydraulic actuator 3 and the head side oil chamber 9 c of the hydraulic cylinder 9.
Further, on the downstream side 15b of the second oil passage 15, assuming that the head side oil chamber 3c of the hydraulic actuator 3 is the upstream side and the head side oil chamber 9c of the hydraulic cylinder 9 is the downstream side, from the upstream side toward the downstream side. The pilot check valve 13c and the third check valve 13b are provided in this order.
Since other configurations are the same as those in the first embodiment, description thereof will be omitted.

(Effect of 2nd Embodiment)
The hydraulic circuit 101 of the hydraulic device according to the second embodiment has the following effects.
(1) According to the hydraulic circuit 101 of the hydraulic device according to the second embodiment, the first oil passage 14 and the second oil passage 15 are each composed of a separate line from the head-side oil passage 4.
According to such a configuration, the first oil passage 14 and the second oil passage 15 that supply and discharge the hydraulic oil to and from the hydraulic cylinder 9 are configured by separate lines from the head-side oil passage 4. So there is little pressure loss. Therefore, it is possible to reduce the reduction effect of the reduction speed of the hydraulic actuator 3 due to the pressure loss.

(Modification of the second embodiment)
FIG. 5 is a configuration diagram of a hydraulic circuit 102 of a hydraulic device according to a modified example of the second embodiment.
This modification is different from the second embodiment in that the first oil passage 14 and the second oil passage 15 are configured as independent pipe lines. According to this modification, the passage area is doubled if the first oil passage 14 and the second oil passage 15 are configured by piping parts having the same diameter, so that the pressure loss can be further reduced. However, in this modification, the port must be opened at two places (three places when combined with a normal switching circuit) in the head side oil chamber 3c of the hydraulic actuator 3.

(Third embodiment)
Next, a third embodiment of the present invention will be described with reference to the drawings. In addition, about the structure similar to 1st Embodiment, the same code | symbol is used and the detail is abbreviate | omitted.
FIG. 6 is a configuration diagram of the hydraulic circuit 103 of the hydraulic device according to the third embodiment of the present invention.
The third embodiment is a pipeline in which the first oil passage 14 is branched from the head-side oil passage 4 and the second oil passage 15 is composed of a pipeline of a different system from the head-side oil passage 4 in the first implementation. Different from form. Specifically, as shown in FIG. 6, in the third embodiment, the first oil passage 14 has the same configuration as the first oil passage 10 of the first embodiment, and the second oil passage 15 is the second embodiment. The second oil passage 15 has the same configuration.
Since other configurations are the same as those in the first embodiment, description thereof will be omitted.

(Effect of the third embodiment)
The hydraulic circuit 103 of the hydraulic device according to the third embodiment has the following effects.
(1) According to the hydraulic circuit 103 of the hydraulic equipment according to the third embodiment, the first oil passage 14 is a pipe branched from the head side oil passage 4, and the second oil passage 15 is connected to the head side oil passage 4. Consists of a separate line.
In the present invention, when the hydraulic actuator 3 is reduced, the pressure oil in the head side oil chamber 3c of the hydraulic actuator 3 flows into the head side oil chamber 9c of the hydraulic cylinder 9 to improve the reduction speed. In the first embodiment, as shown in FIG. 3, the hydraulic cylinder 9 is operated by a pressure receiving area difference between the head side oil chamber 9c and the rod side oil chamber 9b. In contrast, in the third embodiment, the hydraulic cylinder 9 is operated by the total pressure receiving area of the head-side oil chamber 9c, so that the operating speed of the hydraulic cylinder 9 can be further increased. Therefore, in the third embodiment, the flow of the pressure oil from the hydraulic actuator 3 side to the hydraulic cylinder 9 side is performed quickly, which is preferable for improving the reduction speed of the hydraulic actuator 3 that is the object of the present invention.

2 Hydraulic pump 3 Hydraulic actuator 3b Rod side oil chamber 3c Head side oil chamber 3d Piston 3e Piston rod 4 Head side oil passage 5 Rod side oil passage 6 Hydraulic oil tank 7 Control valve 8 Speed increasing valve 8a First sequence valve 8b First Check valve 8c Second check valve 8d Second sequence valve 8e Fourth oil passage 8f Differential oil passage 9 Hydraulic cylinder 9a Cylinder tube 9b Rod side oil chamber 9c Head side oil chamber 9d Piston 9e Piston rod 10 First oil passage 11 First 2 oil passage 12 third oil passage 13 oil passage opening / closing state control unit 13a reverse pilot check valve 13b third check valve 13c pilot check valve 14 first oil passage 15 second oil passage

Claims (7)

A hydraulic pump that discharges hydraulic oil;
A hydraulic actuator that expands and contracts with hydraulic oil discharged from the hydraulic pump;
A head side oil passage connected to a head side oil chamber of the hydraulic actuator;
A rod-side oil passage connected to a rod-side oil chamber of the hydraulic actuator;
A hydraulic oil tank for collecting the hydraulic oil;
During the extension operation of the hydraulic actuator, the discharge side of the hydraulic pump and the head side oil passage are connected, the hydraulic oil tank and the rod side oil passage are connected, and during the reduction operation of the hydraulic actuator, A control valve for connecting the discharge side of the hydraulic pump and the rod side oil passage, and for connecting the hydraulic oil tank and the head side oil passage;
A hydraulic cylinder for accumulating hydraulic oil;
A first oil passage connecting the rod side oil chamber of the hydraulic cylinder and the head side oil chamber of the hydraulic actuator;
A second oil passage connecting the head side oil chamber of the hydraulic cylinder and the head side oil chamber of the hydraulic actuator;
A third oil passage connecting the head side oil chamber of the hydraulic cylinder and the hydraulic oil tank;
When the hydraulic actuator is extended, the second oil passage is closed, and the third oil passage is opened. When the hydraulic actuator is reduced, the second oil passage is opened, and the third oil passage is opened. A hydraulic circuit for a hydraulic device, comprising: an oil path open / close state control unit configured to close the path.   2. The hydraulic circuit for hydraulic equipment according to claim 1, wherein the first oil passage and the second oil passage are pipes branched from the head-side oil passage. 3.   2. The hydraulic circuit for a hydraulic device according to claim 1, wherein the first oil passage and the second oil passage are pipes of different systems from the head-side oil passage. 3.   The said 1st oil path is a pipe line branched from the said head side oil path, The said 2nd oil path consists of a pipe line of a different system from the said head side oil path. Hydraulic circuit for hydraulic equipment. The oil passage opening / closing state control unit is
A reverse pilot check valve that is installed in the third oil passage and is in a valve-open state when the oil pressure in the rod-side oil passage is equal to or lower than a predetermined set pressure;
A check valve that is installed in the second oil passage and allows hydraulic fluid to flow from the head side oil chamber side of the hydraulic actuator to the head side oil chamber side of the hydraulic cylinder;
A pilot check valve that is installed in the second oil passage between the check valve and a head-side oil chamber of the hydraulic actuator, and that opens when the oil pressure in the rod-side oil passage exceeds the set pressure; 5. The hydraulic circuit for hydraulic equipment according to claim 1, comprising:   6. A speed increasing valve is provided to increase the extension speed of the hydraulic actuator by flowing hydraulic oil from the rod side oil path to the head side oil path during the extension operation of the hydraulic actuator. The hydraulic circuit of the hydraulic equipment of any one of these. The speed increasing valve is
A differential oil path check valve that is installed in a differential oil path connecting the rod side oil path and the head side oil path, and that allows hydraulic oil to flow from the rod side oil path side to the head side oil path side; ,
When the differential oil passage check valve and the rod side oil passage are installed in the differential oil passage, and when the hydraulic pressure in the head side oil passage is equal to or higher than a predetermined set pressure, the valve is opened. The hydraulic circuit for hydraulic equipment according to claim 6, further comprising: a differential hydraulic path sequence valve.

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