JP3198163B2 - Hydraulic drive for construction machinery - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hydraulic drive device for a construction machine such as a hydraulic excavator or a crane, and more particularly, to adjusting the opening of a regeneration circuit when an actuator freely falls, such as an arm cloud operation of a hydraulic excavator. The present invention relates to a hydraulic drive device for a construction machine suitable for appropriately setting a speed in both a single operation and a combined operation.

[0002]

2. Description of the Related Art For example, Japanese Patent Laid-Open Publication No. 63-83808 and Japanese Patent Laid-Open Publication No.
As described in Japanese Patent Application Publication No. 04-2004, etc., a so-called regeneration circuit that allows the return pressure oil of the hydraulic actuator to flow into the supply side of the actuator and compensates for the shortage of supply-side pressure oil at the time of free fall of the actuator and enables the actuator to speed up. What is provided is known.

[0003] On the other hand, in the hydraulic drive system for a construction machine, be subjected feeding into one accession <br/> Chue data and joins the pressure oil from the two hydraulic pumps have been performed, pressure to the actuator Two switching valves are provided corresponding to the two hydraulic pumps for supplying oil.

[0004]

When a regeneration circuit is provided in a hydraulic drive unit that combines pressure oils from two hydraulic pumps and supplies one actuator, the return from the actuator when the actuator is operated in one direction. A meter-out restrictor is provided on the discharge passage for discharging the pressurized oil to the tank, and the supply passage for supplying the pressurized oil to the actuator when the actuator is operated in the same one direction and the discharge passage are connected by a regeneration line. A regeneration circuit is provided, and the regeneration line is provided with a check valve that allows only the flow of the pressure oil from the discharge passage to the supply passage. According to this reproduction circuit, it is preferable that the actuator can be driven at a high speed during the single operation, but there is a problem that the speed of the actuator becomes unbalanced during the combined operation with another actuator.

That is, for example, in the arm cloud operation of a hydraulic shovel, the arm cloud operation is performed by the arm alone, and then the combined operation with the boom raising operation is performed. 2. The specifications of the regeneration circuit are determined so as to be compatible with the independent operation of the arm cloud into which the pressure oils from the two pumps join and flow. However, when the specifications of the regenerative circuit are determined in this manner, the combined operation with the boom raising operation results in a boom 1 pump and an arm 1 pump. On the other hand, the boom raising speed becomes a low speed equivalent to one pump, while the boom raising speed is equivalent to the high speed, and an imbalance with the arm cloud speed occurs, so that the operation according to the operator's intention cannot be obtained.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a construction in which a high-speed drive can be performed by using a regeneration circuit when a hydraulic actuator is operated alone, and a drive speed balanced with the drive speed of the other actuator is obtained during a combined operation with another actuator. It is to provide a hydraulic drive for the machine.

[0007]

According to the present invention, there is provided, in accordance with the present invention, first and second hydraulic pumps and a hydraulic pump driven by the first and second hydraulic pumps. First and second hydraulic actuators, a first switching valve for supplying pressure oil from the first hydraulic pump to the first hydraulic actuator, and a pressure oil from the second hydraulic pump. A construction machine comprising: a second switching valve for supplying a second hydraulic actuator; and a third switching valve for confluence for supplying hydraulic oil from the first hydraulic pump to the second hydraulic actuator. (A) driving the second hydraulic actuator in one direction;
Said second supply passage for supplying the second hydraulic actuator through the second selector valve pressure oil from the hydraulic pump when moving; (b) the second hydraulic actuator
A discharge passage for discharging return pressure oil from the second actuator to the tank through the second switching valve when the motor is driven in the one direction ; and (c) a first passage provided on the discharge passage. Throttle means; (d) a regeneration path connecting the discharge path and the supply path to form a regeneration circuit; (e)
A second throttle means for regeneration adjustment provided in the regeneration passage and a check valve for allowing only the flow of pressure oil from the discharge passage to the supply passage; and (f) outputting a regeneration operation signal operated by the operator. (G) opening degree adjusting means for adjusting the opening area of the second throttle means in response to a reproducing operation signal from the reproducing operation means. A drive is provided.

[0008] In the above hydraulic drive device, preferably,
The reproduction operation means is an operation instruction means for outputting an operation instruction signal of the first actuator as the reproduction operation signal. The reproduction operation means may be an external operation means for outputting a dedicated signal as the reproduction operation signal.

In the above-mentioned hydraulic drive device, preferably, the opening degree adjusting means continuously adjusts the opening area of the second throttle means so that the opening area decreases as the reproduction operation signal increases. Adjust to When the reproduction operation signal is small, the opening degree adjusting means may control the second position.
The aperture area of the aperture means is opened to the maximum, and when the reproduction operation signal slightly increases, the aperture area of the second aperture means becomes zero.
The opening area may be adjusted on and off so as to have a small constant size.

[0010] In the above hydraulic drive device, preferably, the first throttle means is provided on a spool of the second switching valve. Note that, for example, in a configuration in which meter-in and meter-out can operate independently, the meter-out diaphragm serves as the first diaphragm means.

The first throttle means, the second throttle means and the check valve are all provided on a spool of the second switching valve.
The second throttle means may be configured to open with a stroke of the spool that is greater than a stroke of the first throttle means with an opening.

In this case, preferably, the regeneration operation means drives the first hydraulic actuator in one direction.
A pilot valve which generates a pilot pressure for operating the first switching valve when the opening degree adjustment means,
Based on the pilot pressure, the second hydraulic
The pilot pressure for operating the second switching valve when driving the waiter in the one direction is corrected, and the spool stroke of the second switching valve is corrected by the corrected pilot pressure.

Further, the regeneration operation means is a hydraulic pilot valve for generating a dedicated pilot pressure as the regeneration operation signal, and the opening adjustment means controls the second hydraulic actuator based on the pilot pressure. Said one
The pilot pressure for operating the second switching valve when driving in the direction may be corrected, and the spool stroke of the second switching valve may be corrected using the corrected pilot pressure.

[0014]

When the second hydraulic actuator is operated alone,
The opening adjustment means adjusts the opening area of the second aperture means so as to increase the opening area in accordance with the reproduction operation signal of the reproduction operation means, and thereby a sufficient regeneration flow rate can be secured using the reproduction circuit. The drive speed of the second hydraulic actuator can be increased to the maximum. At the time of the combined operation of the second hydraulic actuator and the first hydraulic actuator, the opening adjustment means adjusts the opening area of the second throttle means so as to be 0 or smaller in accordance with the regeneration operation signal of the regeneration operation means, As a result, the regeneration flow rate flowing through the regeneration circuit becomes zero or less, so that the drive speed of the second hydraulic actuator can be balanced with the drive speed of the first hydraulic actuator, and good composite operability is obtained.

The regeneration operation means is an operation instruction means for outputting an operation instruction signal for the first actuator, and adjusts an opening area of the second throttle means in accordance with the operation instruction signal to thereby provide a second hydraulic pressure. Since the operation command signal of the first actuator is 0 when the actuator is operated alone, the opening area of the second throttle means can be adjusted so as to increase, and during the combined operation with the first hydraulic actuator, the operation of the first actuator is controlled. Since the operation command signal is output at a certain magnitude, it can be adjusted so that the opening area of the second aperture means is reduced to zero or small.

The reproduction operation means is an external operation means for outputting a dedicated signal, and by adjusting the opening area of the second aperture means in accordance with the signal, the external operation means can be controlled in advance during the single operation and the composite operation. If a signal is given by operation, the aperture area of the second diaphragm means can be adjusted in the same manner as described above. Further, in this case, the use / non-use of the reproduction passage can be switched according to a signal from the external operation means, so that the operator can select a drive characteristic suitable for the work content or the work environment.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the present invention will be described with reference to FIGS.
A hydraulic excavator will be described as an example of a construction machine. FIG.
In this embodiment, the hydraulic drive device of the present embodiment includes two hydraulic pumps 1 and 2, regulators 3 and 4 for adjusting the discharge amounts of the hydraulic pumps 1 and 2, respectively, and hydraulic oil discharged from the hydraulic pumps 1 and 2. Respectively, two hydraulic actuators for driving a boom and an arm (not shown), namely a boom cylinder 5 and an arm cylinder 6,
Two switching valves 7 and 8 for supplying hydraulic oil from the hydraulic pump 1 to the actuators 5 and 6, respectively, and two switching valves 9 and 10 for supplying hydraulic oil from the hydraulic pump 2 to the actuators 5 and 6, respectively. Have. The switching valves 7 and 8 are connected to the hydraulic pump 1 in tandem so that the pressure oil is supplied to the switching valve 7 preferentially, and the switching valves 9 and 10 are connected to the hydraulic pump 2 in parallel. The switching valves 7 and 10 have their actuator ports connected to the head side and the rod side of the actuator 5 via a pair of actuator lines 5a and 5b, respectively, and the switching valves 8 and 9 have their actuator ports connected in a pair. Are connected to the head side and the rod side of the actuator 6 via the actuator lines 6a and 6b, respectively. The actuator line 5a is provided with a check valve 5c that allows only the flow of pressure oil from the switching valve 10 to the head side of the actuator 5, and the actuator line 6b is used to supply pressure oil from the switching valve 8 to the rod side of the actuator 6. A check valve 6c that allows only flow is provided.

The switching valve 9 is provided with a meter-out throttle 9a. The meter-out throttle 9a is provided on the spool of the switching valve 9, and is located on a discharge passage when the actuator 6 is driven in the extension direction. Also,
The actuator lines 6a and 6b are connected to each other by a reproduction line 6d to form a reproduction circuit. A regeneration adjustment valve 1 having a regeneration adjustment aperture 14b on the regeneration line 6d
4 and a check valve 15 that allows only the flow of pressure oil from the actuator line 6b to the actuator line 6a. That is, the actuator line 6b serves as a discharge passage for driving the actuator 6 in the extension direction, and the actuator line 6a serves as a supply passage for driving the actuator 6 in the extension direction. Connect to the passage and check valve 1
5 is provided so as to allow only the flow of the pressure oil from the discharge passage to the supply passage. The switching valves 7, 8, 9, 10 and the regeneration adjustment valve 14 are both electromagnetically operated valves.

The hydraulic drive device of the present embodiment is operated by an operator and outputs operation command signals 11a and 12a for the actuators 5 and 6 , respectively.
Switching valves 7, 8, 9, 10 based on pressure detectors 3 a, 4 a for detecting discharge pressures of hydraulic pumps 1, 2 and operation command signals 11 a, 12 a from operation command devices 11, 12.
Drive signals 7U, 7L; 8C, 8D; 9C, 9D; 1
A control unit 13 that outputs a drive signal 14a to 0U, 10L and the regeneration adjustment valve 14, and outputs a drive signal for the regulators 3, 4 based on signals from the pressure detectors 3a, 4a. Here, the operation command device 11
Is also operated by an operator to output a reproduction operation signal, and the operation command signal 11a is a reproduction operation signal in this case.

The control unit 13 is composed of a microcomputer, and as shown in FIG.
2 and the pressure detector 3
an A / D converter 13a for converting signals from a and 3b into digital signals, a central processing unit (CPU) 13b,
A read-only memory (ROM) 13c for storing a control procedure program, a randem access memory (RAM) 13d for temporarily storing numerical values during the operation, an I / O interface 13e for output, and an I / O interface 13e to amplify the signal from the switching valve 7,
8, 9, 10, regeneration regulating valve 14 and regulators 3, 4
And an amplifying unit 13f for outputting the signal.

FIG. 3 shows a driving signal 7 of the control unit 13.
U, 7L; 8C, 8D; 9C, 9D; 10U, 10L and the calculation function of the drive signal 14a are shown in a block diagram. FIG.
, Blocks 21 to 25 are function generating functions, block 26 is a multiplying function, and blocks 27 to 35 are amplifying functions and correspond to the amplifying unit 13f in FIG. Operation command device 1
1 is converted into a boom raising operation signal U and a boom lowering operation signal L in blocks 21 and 22, respectively. The operation command signal 12a from the operation command device 12 is converted into an arm cloud operation signal in blocks 23 and 24, respectively. C and an arm dump operation signal D, and these converted signals U, L, C, and D are converted to a block 27.
And the drive signals 7U, 10U, 7
L, 10L, 8C, 9C, 8D, 9D as switching valve 7,
8, 9, and 10 are output. The operation command signal 11a for the boom raising operation is a reproduction operation signal, and the converted signal U is converted into a correction signal S in a block 25. Here, the block 25 determines whether S = 0 and U = 0 for the converted signal U.
= 1, S = S0 when U ≧ U0, and a value of S that continuously decreases as U increases when 0 <U <U0. Further, the conversion signal C of the arm cloud operation and the correction signal S are multiplied in a block 26 to become a reproduction adjustment signal Ca. The reproduction adjustment signal C a is amplified in block 35, it is outputted to the reproduction control valve 14 as the drive signal 14a. Here, the blocks 25 and 26 control the reproduction adjustment aperture 14 in response to the operation command signal (reproduction operation signal) 11 a of the actuator 5.
The opening degree adjusting means for controlling the opening area of a is constituted.

FIG. 4 shows the change in the opening area of the reproduction adjustment aperture 14b by the adjustment function of the opening adjustment means constituted by the blocks 25 and 26. 4, the horizontal axis represents the arm cloud operation command amount, which corresponds to the magnitude of the operation command signal 12a when performing the arm cloud operation, that is, the magnitude of the conversion signal C in FIG. The vertical axis is the opening area of the meter-out aperture 9a and the reproduction adjustment aperture 14b. The dashed-dotted line indicates the opening characteristics of the meter-out aperture 9a during the arm cloud operation, and the solid lines a1 to an indicate the opening characteristics of the reproduction adjustment aperture 14b during the arm cloud operation using the boom raising operation command amount as a parameter. Here, the boom raising operation command amount is an operation command signal (reproduction operation signal) for performing the boom raising operation.
11a, that is, the size of the converted signal U in FIG.

When the arm cloud is operated alone, since the operation command signal 11a in FIG. 3 is 0 and the conversion signal U is also 0, the correction signal S is 1, and the conversion signal for the arm cloud operation (the arm cloud operation command amount) is output from the block 26. C) is output as the reproduction adjustment signal Ca as it is, and when the arm cloud operation command amount exceeds a predetermined value, an opening degree characteristic a1 in which the opening area of the reproduction adjustment diaphragm 14b is larger than the opening area of the meter-out diaphragm 9a is obtained.

In the combined operation of the arm cloud and the boom raising, the conversion signal U of the boom raising operation shown in FIG. 3 has a magnitude corresponding to the boom raising operation command amount, and the correction signal S has a magnitude corresponding to the magnitude of the conversion signal U. The value is 1 or less. Block 26
Then, the correction signal S of 1 or less is multiplied by the converted signal C of the arm cloud operation. Therefore, the reproduction adjustment signal C
a also becomes smaller than the conversion signal C in accordance with the correction signal S, and the aperture area of the reproduction adjustment aperture 14b is smaller than the aperture area when the arm cloud is operated alone and the aperture area of the meter-out aperture 9a as shown by a2, for example. Become. The correction signal S is a conversion signal U for the boom raising operation in the range of 0 <U <U _0.
Becomes larger continuously, the opening area of the reproduction adjustment aperture 14 also decreases continuously as the boom raising operation command amount increases, and the opening characteristics of the reproduction adjustment aperture 14 are like a2 to an. Changes to

The function of the control unit 13 for calculating the drive signals of the regulators 3 and 4 is such that the input torque of the hydraulic pumps 1 and 2 is within the range of the output torque of a prime mover (not shown) for driving these pumps. , 4a are calculated based on the signals from the regulators 3 and 4,
A so-called known input torque limiting control for limiting the maximum value of the displacement of the hydraulic pumps 1 and 2 is performed, and details thereof are omitted.

Next, the operation of the present embodiment configured as described above will be described. During the independent operation of raising the boom, the pressure oil from the hydraulic pumps 1 and 2 is supplied to the head side of the hydraulic actuator 5 via the switching valves 7 and 10, and the return pressure oil from the rod side is supplied via the switching valves 7 and 10. Drained into tank. When the arm cloud is operated alone, the hydraulic pumps 1, 2
Is supplied to the head side of the hydraulic actuator 6 via the switching valves 8 and 9, and return pressure oil from the rod side is discharged to the tank via the meter-out throttle 9 a of the switching valve 9. At this time, since the boom raising operation has not been performed,
Since the conversion signal U = 0 and the correction signal S = 1 in FIG. 3, the reproduction adjustment signal Ca has the same value as the conversion signal C of the arm cloud operation as described above, and the opening degree characteristic a1 in FIG. As described above, the reproduction adjustment aperture 14b is operated from fully closed to the maximum opening in accordance with the arm cloud operation command amount. Thereby, the actuator line (discharge passage) 6
b, a sufficient regeneration flow rate can be made to flow into the actuator line (supply passage) 6a by using a regeneration circuit,
The high-speed driving of the actuator 6 becomes possible while compensating for the shortage of pressure oil on the head side when the actuator 6 is freely lowered.

Here, when the combined operation of the boom raising and the arm cloud is performed, the correction signal S decreases from 1 and changes to a predetermined magnitude S ₀ as the converted signal U of the boom raising operation increases. Therefore, the reproduction adjustment signal Ca has a small value equal to or smaller than the conversion signal C of the arm cloud operation according to the magnitude of the correction signal S, and the opening degree characteristics a2 to an corresponding to the boom raising operation command amount are obtained. That is, the opening area of the regeneration adjustment aperture 14b is smaller in the combined operation than in the arm cloud alone operation, and the regeneration flow rate flowing from the actuator line (discharge passage) 6b to the actuator line (supply passage) 6a is smaller. The operation speed of the cloud approaches the flow rate determined by the meter-out throttle 9a. On the other hand, the pressure oil from the hydraulic pump 2 hardly flows to the actuator 5 on the high pressure side because the actuator 6 is on the low pressure side. Therefore,
In the combined operation with the boom raising operation, the operation becomes one boom pump / one arm pump and the regeneration flow rate flowing through the regeneration circuit is reduced, so that the operation speed of the arm cloud balanced with the operation speed of the boom raising can be obtained.

Therefore, according to the present embodiment, the actuator 6 can be driven at a high speed when the arm cloud is operated alone, and when the arm cloud and the boom raising are combined, the operation speed of the arm cloud balanced with the operating speed of the boom raising is achieved. And good composite operability can be ensured.

A second embodiment of the present invention will be described with reference to FIG. In the figure, functions equivalent to those shown in FIG. 3 are denoted by the same reference numerals. In the first embodiment, the opening area of the reproduction adjustment aperture is continuously adjusted in response to the operation command signal (reproduction operation signal) for raising the boom. In the present embodiment, this is switched on and off.

In FIG. 5, a block 25A is a function generating function replacing the block 25 in FIG. 3, and when the conversion signal U of the boom raising operation is a small value including U = 0, S = S
Outputs the first correction signal S, U outputs a slightly larger small constant value of S = S _0. Thus, the opening characteristic of the reproduction adjustment aperture 14b (see FIG. 1) with respect to the arm cloud operation command amount is such that the conversion signal U =
Since the correction signal S is 0 and the correction signal S is 1, as shown in a1 of FIG. 4 similar to the first embodiment, in the combined operation of the arm cloud and the boom raising, when the conversion signal U becomes slightly larger, S =
Since a small constant value of S _0, switched on and off manner in an in FIG.

Therefore, also in this embodiment, since the aperture area of the reproduction adjustment aperture 14b becomes large when the arm cloud is operated alone, it is possible to increase the operation speed of the arm cloud by securing a sufficient reproduction flow rate by using the reproduction circuit. In the combined operation of the boom raising and the arm cloud, the opening area of the reproduction adjustment aperture 14b becomes small, so that the reproduction flow rate flowing through the reproduction circuit can be reduced to obtain the operation speed of the arm cloud balanced with the operation speed of the boom raising. Thus, effects similar to those of the first embodiment can be obtained.

A third embodiment of the present invention will be described with reference to FIGS. In the figure, members and functions equivalent to those in FIGS. 1 and 3 are denoted by the same reference numerals. In the above embodiment, the opening area of the reproduction adjustment aperture is controlled according to the boom raising operation command signal. However, in this embodiment, a dedicated external operation means is provided as the reproduction operation means.

In FIG. 6, the hydraulic drive device of this embodiment further has an external operation device 36 for outputting a signal V corresponding to an operation amount as a reproduction operation means operated by an operator to output a reproduction operation signal. I have. External operation device 36
Is taken into the control unit 13B.

In FIG. 7, a block 25B is a function generating function replacing the block 25 in FIG. 3, and the reproduction operation signal V from the external operation device 36 is converted into a correction signal S in the block 25B. Block 25B has the same function generation function as block 25 in FIG. That is, for the reproduction operation signal V, S = 1 when V = ₀ and S = S when V ≧ V _0
0 , a value of V that continuously decreases as V increases when 0 <V <V ₀ is output. Thereby, when the reproduction operation signal V from the external operation device 36 is set to 0, the correction signal S becomes 1, and the opening characteristic of the reproduction adjustment aperture 14b is a1 in FIG.
When the external operation device 36 is operated to increase the reproduction operation signal V, the correction signal S has a magnitude of 1 or less corresponding to the magnitude of the reproduction operation signal V, and the reproduction adjustment aperture 14b
The opening characteristic changes as a2 to an in FIG. 4 according to the magnitude of the reproduction operation signal V.

Therefore, also in this embodiment, when the arm cloud is operated alone, the opening of the reproduction adjustment aperture 14b is increased by setting the reproduction operation signal V to 0 in advance. And the operation speed of the arm cloud can be increased, and the playback operation signal V
Is set to a predetermined size, so that the reproduction adjustment aperture 14 can be adjusted.
Since the opening area of b becomes small, the operation flow rate of the arm cloud balanced with the operation speed of the boom raising can be obtained by reducing the regeneration flow rate flowing through the regeneration circuit, and the same effect as in the first embodiment can be obtained. Can be.

Further, according to the present embodiment, the use / non-use of the reproduction circuit can be switched in accordance with the reproduction operation signal V from the external operation device. Can be selected.

A fourth embodiment of the present invention will be described with reference to FIGS. In the figure, the same reference numerals are given to members equivalent to the members shown in FIG. In the above-described embodiment, the reproduction adjustment diaphragm is electrically controlled by using the control unit. In the present embodiment, this is hydraulically controlled.

Referring to FIG. 8, the hydraulic drive device of the present embodiment includes switching valves 7P, 8P, 9 of a hydraulic pilot operation type.
P, 10P and a hydraulic pilot valve 1 for generating pilot pressures PU, PL for operating the switching valves 7P, 10P as operation command signals for the hydraulic actuator 5, respectively.
6, 17 and a pilot pressure P for operating the switching valves 8P, 9P as an operation command signal for the hydraulic actuator 6.
Hydraulic pilot valves 18 and 1 for generating C and PD, respectively
9 and the pilot pressure PU from the hydraulic pilot valve 16
Pilot pressure P from hydraulic pilot valve 18 according to
A pressure reducing valve 20 for reducing the pressure of C to generate a corrected pilot pressure PCa. The hydraulic pilot valves 16 to 19 are operated by an operator, and generate pilot pressures PU, PL, PC, and PD according to the operation amounts.

The switching valve 9P is provided with a meter-out throttle 9a as in the first embodiment. Also, switching valve 9P
In the spool, there is a regeneration adjustment throttle 14C and a check valve 15C.
Is provided. That is, the discharge line and the actuator line 6 where the meter-out throttle 9a in the switching valve 9P is located
The supply passage connectable to the reproduction line 6a is connected to the supply path via a reproduction line 6e.
C and a check valve 15C are provided. The reproduction adjustment aperture 14C is configured to open at a predetermined stroke or more of the spool. The hydraulic pilot valve 16 is also operated as a regeneration operation means that is operated by an operator and outputs a regeneration operation signal, and the pilot pressure PU is a regeneration operation signal in this case.

The regulators 3C and 4C for adjusting the discharge amounts of the hydraulic pumps 1 and 2 respectively perform the input torque limiting control by hydraulically limiting the maximum value of the displacement in correspondence with the hydraulic control of the regeneration adjustment throttle.

FIG. 9 shows a change in the opening area of the meter-out aperture 9a and the regeneration adjustment aperture 14C by the adjusting function of the pressure reducing valve 20. In FIG. 9, the horizontal axis represents the arm cloud operation command amount, which corresponds to the magnitude of the pilot pressure PC when performing the arm cloud operation. The vertical axis is the opening area of the meter-out aperture 9a and the reproduction adjustment aperture 14C. The dashed lines b1 to bn are the opening characteristics of the meter-out aperture 9a at the time of arm cloud operation using the boom raising operation command amount as a parameter, and the solid lines a1 to an are those at the time of arm cloud operation using the boom raising operation command amount as a parameter. This is the opening characteristic of the reproduction adjustment aperture 14C. Here, the boom raising operation command amount is the pilot pressure P at the time of performing the boom raising operation.
It corresponds to the magnitude of U (reproduction operation signal).

When the arm cloud is operated alone, the pilot pressure PU for the boom raising operation shown in FIG. 8 is 0, so the pilot pressure PC for the arm cloud operation is output as it is from the pressure reducing valve 20 as the corrected pilot pressure PCa. The opening degree characteristic becomes like b1, and the opening degree characteristic of the reproduction adjustment aperture 14C becomes like a1. As can be seen from this figure, the arm cloud operation command amount (pilot pressure PC; spool stroke) at which the reproduction adjustment aperture 14C opens is set to be larger than the arm cloud operation command amount at which the meter-out aperture 9a opens.

In the combined operation of the arm cloud and the boom raising, the pilot pressure PU of the boom raising operation shown in FIG. 8 has a magnitude corresponding to the operation amount of the pilot valve 16 (boom raising operation command amount). Pressure reducing valve 2
By acting on the setting unit of 0, the pilot pressure PC of the arm cloud operation is corrected according to the pilot pressure PU, and the corrected pilot pressure PCa becomes smaller than the pilot pressure PC according to the pilot pressure PU. For this reason, the upper limit of the opening area of the meter-out aperture 9a and the upper limit of the opening area of the reproduction adjustment aperture 14C continuously decrease as the pilot pressure PU (boom raising operation command amount) increases, and the opening degree characteristics of the meter-out aperture 9a. Is b2
bn, and the opening characteristic of the reproduction adjustment aperture 14C changes as a2 to an.

That is, if the pressure receiving area where the pilot pressure PC and the corrected pilot pressure (output pressure) PCa of the pressure reducing valve 20 act is A1, the pressure receiving area where the pilot pressure PU acts is A2, and the spring load is FS, PCa = PC + FS / A1−PU * A2 / A1 holds, and when PU is equal to or less than a predetermined value FS / A2, P
Ca = PC, and when PU becomes FS / A2 or more, PC
Since a is a constant pressure smaller than PC in accordance with the size of PU, even when the pilot pressure PC for arm cloud operation is operated at the maximum, as the pilot pressure PU for boom raising operation increases, FIG. A1 of 9
The opening area of the regeneration adjustment aperture 14C becomes smaller as in an, and as a result, the regeneration flow rate decreases, and the opening area of the regeneration adjustment aperture 14C as in an can be reduced to the fully closed or close to it.

Therefore, according to the present embodiment, since the opening of the regeneration adjusting aperture 14C is large when the arm cloud is operated alone, a sufficient regeneration flow rate can be secured by using the regeneration circuit to increase the operation speed of the arm cloud. In the combined operation of the boom raising and the arm cloud, the opening area of the reproduction adjustment aperture 14C is reduced, so that the reproduction flow rate flowing through the reproduction circuit can be reduced to obtain the operation speed of the arm cloud balanced with the operation speed of the boom raising. Thus, effects similar to those of the first embodiment can be obtained.

The fifth and sixth embodiments of the present invention will be described with reference to FIGS. 10 and 11, respectively. In the drawing, the same reference numerals are given to members equivalent to the members shown in FIG. These embodiments are embodiments in which the regeneration adjustment diaphragm is hydraulically controlled as shown in FIG. 8, and in which the opening area of the regeneration adjustment diaphragm is switched on / off as shown in FIG. The modification similar to that of the embodiment in which the opening area of the reproduction adjustment aperture is controlled in accordance with the reproduction operation signal from the reproduction operation means is performed.

That is, in FIG. 10, the pressure reducing valve 20 of FIG.
Instead of the pressure reducing valve 20D for generating a small constant pilot pressure PC0 and the pilot pressure PU for the boom raising operation
The selection valve 37 which switches by this is arrange | positioned. When the pilot pressure PU of the boom raising operation is a small value,
The selection valve 37 is at the position shown in the figure, and the pilot pressure PC for the arm cloud operation is directly corrected for the pilot pressure PC.
Output as a. Thereby, the meter-out aperture 9a and the reproduction adjustment aperture 1 for the arm cloud operation command amount are set.
The opening characteristics of 4C are as shown by b1 and a1 in FIG.
When the pilot pressure PU of the boom raising operation exceeds a predetermined value, the selection valve 37 is switched from the position shown in FIG.
The small constant pilot pressure PC0 from D is output as the corrected pilot pressure PCa. Accordingly, the opening degree characteristics of the meter-out aperture 9a and the reproduction adjustment aperture 14C with respect to the arm cloud operation command amount are, for example, b shown in FIG.
n, an, and b1, a1 through bn,
Switches to an on and off.

On the other hand, the embodiment shown in FIG. 11 is operated by an operator and uses a dedicated pilot pressure PV as a regeneration operation means for outputting a regeneration operation signal corresponding to the operation amount.
Is further provided.
The pilot pressure PV from the hydraulic pilot valve 36E is led to the setting section of the pressure reducing valve 20 instead of the pilot pressure PU in the embodiment of FIG. Thereby, when the hydraulic pilot valve 36E is not operated and the pilot pressure PV is 0, the pilot pressure PC for the arm cloud operation is output as it is from the pressure reducing valve 20 as the corrected pilot pressure PCa, and the opening degree characteristic of the meter-out throttle 9a. Becomes like b1, and the opening characteristic of the reproduction adjustment aperture 14C becomes like a1. When the pilot pressure PV is increased by operating the hydraulic pilot valve 36E, the pilot pressure PV acts on the setting portion of the pressure reducing valve 20, so that the pilot pressure PC of the arm cloud operation is corrected according to the pilot pressure PV, and the corrected pilot pressure PCa becomes a value smaller than pilot pressure PC according to pilot pressure PV. For this reason, the opening characteristic of the meter-out aperture 9a changes as b2 to bn, and the opening characteristic of the reproduction adjustment aperture 14C is a2 to bn.
It changes like an.

Therefore, according to the present embodiment, when the arm cloud is operated alone, the regeneration circuit can be used to secure a sufficient regeneration flow rate to increase the operation speed of the arm cloud. By reducing the regeneration flow rate flowing through the regeneration circuit, the operation speed of the arm cloud balanced with the operation speed for raising the boom can be obtained, and the same effect as that of the first embodiment can be obtained.

Further, according to the embodiment of FIG. 11, the use / non-use of the regeneration circuit can be switched in accordance with the pilot pressure PV from the hydraulic pilot valve 36E. It is possible to select a drive characteristic suitable for the environment.

In the above embodiment, the regeneration line is connected to the downstream side of the meter-in throttle and the regeneration flow is merged with the downstream side of the meter-in throttle. A configuration in which the flow rate is joined to the upstream side of the meter-in throttle may be employed . Although the meter-out throttle is provided on the spool of the switching valve, the meter-in throttle and the meter-out throttle may be configured to operate independently.

[0052]

According to the present invention, when the actuator is operated alone, the regeneration speed can be increased by using the regeneration circuit to the maximum and the driving speed can be increased. By reducing the flowing regeneration flow rate, it is possible to obtain a speed balanced with the driving speed of the other actuators, and it is possible to ensure good composite operability.

Further, if the use or non-use of the reproducing circuit is switched according to the setting signal from the external operation means,
A drive characteristic suitable for the work content or work environment can be selected by the operator.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of a hydraulic drive device for a construction machine according to a first embodiment of the present invention.

FIG. 2 is a diagram showing a configuration of a control unit shown in FIG.

FIG. 3 is a block diagram showing processing contents in a control unit shown in FIG. 1;

FIG. 4 is a diagram showing a change in an opening degree characteristic of a reproduction adjustment aperture in the embodiment shown in FIG. 1;

FIG. 5 is a block diagram similar to FIG. 3, showing processing contents of a control unit in a hydraulic drive device for a construction machine according to a second embodiment of the present invention.

FIG. 6 is a schematic configuration diagram of a hydraulic drive device for a construction machine according to a third embodiment of the present invention.

FIG. 7 is a block diagram showing processing contents in a control unit shown in FIG. 6;

FIG. 8 is a schematic configuration diagram of a hydraulic drive device for a construction machine according to a fourth embodiment of the present invention.

FIG. 9 is a diagram showing a change in the opening degree characteristic of a reproduction adjustment aperture in the embodiment shown in FIG. 8;

FIG. 10 is a schematic configuration diagram of a hydraulic drive device for a construction machine according to a fifth embodiment of the present invention.

FIG. 11 is a schematic configuration diagram of a hydraulic drive device for a construction machine according to a sixth embodiment of the present invention.

[Explanation of symbols]

1, 2 Hydraulic pump 5, 6 Hydraulic actuator 6d; 6e Regeneration line (regeneration circuit) 7 to 10; 7P to 10P switching valve 9a Meter-out aperture (first aperture means) 11 Operation command device (regeneration operation means) 12 Operation Command device 13; 13B Control unit 14 Regeneration adjustment valve 14b; 14C Regeneration adjustment throttle 15; 15C Check valve 16-19 Hydraulic pilot valve 20 Pressure reducing valve (opening adjustment means) 20D Pressure reducing valve 25; 25A; 25B Function generation function ( Opening degree adjusting means) 26 Multiplication function (Opening degree adjusting means) 36 External operating device (Regenerating operating means) 36E Hydraulic pilot valve (External operating means; Regenerating operating means) 37 Selection valve (Opening degree adjusting means)

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-61-116105 (JP, A) JP-A-2-15648 (JP, U) JP-A-55-49116 (JP, U) (58) Investigation Field (Int.Cl. ⁷ , DB name) E02F 9/22

Claims (9)

(57) [Claims] 1. First and second hydraulic pumps, first and second hydraulic actuators driven by pressure oil discharged from the first and second hydraulic pumps, and the first hydraulic pump A first switching valve for supplying hydraulic oil from the hydraulic pump to the first hydraulic actuator; and a second switching valve for supplying hydraulic oil from the second hydraulic pump to the second hydraulic actuator.
And a third switching valve for merging to supply the hydraulic oil from the first hydraulic pump to the second hydraulic actuator . Drive the hydraulic actuator No. 2 in one direction
A supply passage for supplying pressure oil from the second hydraulic pump to the second hydraulic actuator through the second switching valve when the second hydraulic pump is driven; and (b) driving the second hydraulic actuator in the one direction.
A discharge passage for discharging return pressure oil from the second actuator to the tank through the second switching valve when moving ; (c) first throttle means provided on the discharge passage; (E) a regeneration passage connecting the discharge passage and the supply passage to form a regeneration circuit; and (e) a second throttle means for regeneration adjustment provided in the regeneration passage and a passage from the discharge passage to the supply passage. A check valve that allows only the flow of pressurized oil; (f) regeneration operation means that is operated by an operator to output a regeneration operation signal; and (g) the second throttle according to a regeneration operation signal from the regeneration operation means. And a degree-of-opening adjusting means for adjusting an opening area of the means. 2. The hydraulic drive device for a construction machine according to claim 1, wherein said regeneration operation means is an operation instruction means for outputting an operation instruction signal of said first actuator as said regeneration operation signal. Hydraulic drive for construction machinery. 3. The hydraulic drive system for a construction machine according to claim 1, wherein said regeneration operation means is an external operation means for outputting a dedicated signal as said regeneration operation signal. apparatus. 4. The hydraulic drive device for a construction machine according to claim 1, wherein the opening degree adjusting means is configured to reduce the opening area of the second throttle means as the regeneration operation signal increases. A hydraulic drive for a construction machine, wherein the area is continuously adjusted. 5. The hydraulic drive device for a construction machine according to claim 1, wherein the opening adjustment means opens the opening area of the second throttle means to a maximum when the reproduction operation signal is small,
A hydraulic drive device for a construction machine, wherein the opening area of the second aperture means is adjusted to be on or off so that the opening area of the second aperture means becomes zero or a small constant size when the reproduction operation signal becomes slightly large. 6. A hydraulic drive device for a construction machine according to claim 1, wherein said first throttle means is provided on a spool of said second switching valve. 7. The hydraulic drive system for a construction machine according to claim 1, wherein said first throttle means, second throttle means, and check valve are all provided on a spool of said second switching valve. 2. The hydraulic drive device for a construction machine according to claim 1, wherein the second throttle means is configured to open at a stroke of the spool which is longer than a stroke of the first throttle means. 8. The hydraulic drive device for a construction machine according to claim 7, wherein said regeneration operating means includes a first hydraulic actuator.
A hydraulic pilot valve for generating a pilot pressure for operating the first switching valve when driving the eta in one direction , wherein the opening degree adjusting means controls the second hydraulic actuator based on the pilot pressure. dynamic drive in the one direction
A hydraulic pressure control device for a construction machine, wherein a pilot pressure for operating the second switching valve is corrected when the operation is performed, and a spool stroke of the second switching valve is corrected by the corrected pilot pressure. 9. The hydraulic drive device for a construction machine according to claim 7, wherein said regeneration operation means is a hydraulic pilot valve for generating a dedicated pilot pressure as said regeneration operation signal, and said opening adjustment means is provided with: Drives the second hydraulic actuator in the one direction based on pilot pressure
A hydraulic pressure control device for a construction machine, wherein a pilot pressure for operating the second switching valve is corrected when the operation is performed, and a spool stroke of the second switching valve is corrected by the corrected pilot pressure.