JP2005068718A - Hydraulic drive unit of construction machinery - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce overall pressure loss by reducing the number of flow control valves and a piping connecting length of the flow control valve, and to simplify a layout of hydraulic piping between a hydraulic power source and an actuator receiving pressure oil from the hydraulic power source by reducing the number of the flow control valve. <P>SOLUTION: A hydraulic drive unit is equipped with: control valves 10a-10f for supplying the pressure oil from first hydraulic pumps 1a and 1b in a switching manner; inlet flow control valves 201, 202 and 203 which are provided in branch piping 150A, 150B and 150C for supplying the pressure oil from second hydraulic pumps 3a and 3b to rod push-out side chambers 5aA, 5bB, 6A and 7A of respective hydraulic cylinders by making the pressure oil branch off from a supply line 100; a bypass flow control valve 204 which is provided in piping 104 between the supply pipe 100 and a tank 2; and a controller 31 which computes a controlled variable depending on an operating command signal of control levers 32 and 33, and which controls the control valves 201, 202 and 203 and the control valves 204 by using the controlled variable. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a hydraulic drive device for a construction machine such as a hydraulic excavator, and more particularly to a hydraulic drive device for a construction machine suitable for a so-called super large hydraulic excavator.

  For example, a construction machine such as a super-large hydraulic excavator having a self-weight of 70 t or more, in particular, an upper swing body provided so as to be turnable on the upper portion of the lower traveling body, and a boom rotatably connected to the upper swing body, A so-called backhoe having an arm rotatably connected to the boom, and an articulated front working machine including a bucket that is rotatably connected to the arm so that the opening portion faces rearward in a grounded state. A hydraulic drive device for a construction machine applied to a hydraulic excavator of a type is known (for example, see Patent Document 1).

  This hydraulic drive device is supplied with two hydraulic pumps driven by a first prime mover, two hydraulic pumps driven by a second prime mover, and pressure oil discharged from these four hydraulic pumps, Boom hydraulic cylinder, arm hydraulic cylinder, bucket hydraulic cylinder, and hydraulic pump for boom, arm hydraulic cylinder, and bucket from two hydraulic pumps out of four hydraulic pumps A first control valve group including a boom control valve, an arm control valve, and a bucket control valve that respectively control the flow of pressure oil supplied to the hydraulic cylinder, and the remaining two of the four hydraulic pumps. From hydraulic pump to boom hydraulic cylinder, arm hydraulic cylinder And it comprises a boom control valve for controlling the flow of hydraulic fluid supplied to the hydraulic cylinder for bucket, respectively, the arm control valve, and a second control valve group with a control valve for the bucket. After the pressure oil from the first control valve group and the second control valve group are merged for each of the boom control valve, the arm control valve, and the bucket control valve, the boom hydraulic cylinder and the arm hydraulic pressure are combined. Supplying oil to the cylinder and bucket hydraulic cylinders (in other words, supplying the combined hydraulic oil from the normal hydraulic pump to the control valve), the large amount of hydraulic oil required for the operation of the super large machine Can be supplied to each hydraulic cylinder.

  However, in order to supply pressure oil with an ultra-high pressure and an ultra-high flow rate, it is necessary to construct the main pipe line with ultra-large-diameter hoses and steel pipes. Since it is about 2 inches, a large number (for example, two or three) must be arranged side by side. Therefore, the allowable amount of the main conduit for the supply / discharge flow rate required by the hydraulic actuator is restricted, and a relatively large pressure loss occurs in each hose. Therefore, in the entire hydraulic circuit including long pipes composed of hoses and steel pipes of ultra-large machines, flow control switching valves, etc., very large pressure loss occurs, energy loss increases, and the operating speed of the hydraulic actuator increases. This causes another problem that the work efficiency is lowered.

  Accordingly, in response to the above, a hydraulic drive device for a construction machine has already been proposed to reduce the total pressure loss by reducing the total number of pipes such as the number of hoses and steel pipes in ultra-large machines (for example, patents) Reference 2).

  In this prior art, two hydraulic pumps driven by a first prime mover, two hydraulic pumps driven by a second prime mover, and pressure oil discharged from the four hydraulic pumps are supplied, a boom, Boom hydraulic cylinder, arm hydraulic cylinder, bucket hydraulic cylinder that respectively drive the arm and bucket, and boom hydraulic cylinder, arm hydraulic cylinder, and bucket hydraulic pressure from two of the four hydraulic pumps Boom control valve, arm control valve, and bucket control valve that respectively control the flow of pressure oil supplied to the cylinder, and the remaining two hydraulic pumps, and the boom control valve and arm control described above. Via valve and bucket control valve Boom rod extruding side inflow control valve and boom rod retracting side inflow for controlling the flow of pressure oil supplied to the rod extruding side chamber and rod retracting side chamber of the hydraulic cylinder for boom, arm hydraulic cylinder, bucket hydraulic cylinder, respectively Flow control valve, arm rod extruding side inflow flow rate control valve, arm rod retracting side inflow rate control valve, bucket rod extruding side inflow rate control valve, bucket rod retracting side inflow rate control valve, and the above hydraulic cylinder for boom and arm Boom rod that controls the flow of pressure oil discharged from the hydraulic cylinder and the rod drawing side chamber and the rod extrusion side chamber of the bucket hydraulic cylinder to the tank without going through the boom control valve, arm control valve, and bucket control valve. Inlet side outflow control valve and boom lock Extrusion side outflow control valve, arm rod retracted side outlet flow control valve and the arm rod extrusion side outlet flow control valve, and a bucket rod retracted side outlet flow control Ben及 bucket rod extruded side outlet flow control valve.

  For example, when performing boom raising, arm cloud, and bucket cloud operations, the boom hydraulic cylinder and the arm hydraulic cylinder from the two hydraulic pumps via the boom control valve, the arm control valve, and the bucket control valve. In addition to supplying pressure oil to the rod extrusion side chamber of the hydraulic cylinder for buckets, pressure oil from the remaining two hydraulic pumps was separately provided without going through the boom control valve, arm control valve, and bucket control valve. Pressure via the control valve via a common high pressure pipe and a boom rod extruding side inflow flow rate control valve, arm rod extruding side inflow flow rate control valve, bucket rod extruding side inflow flow rate control valve provided on a common high pressure pipe and a pipe branched and connected thereto. Join the oil flow, Arm hydraulic cylinder, a hydraulic cylinder for arm, supplied to the rod extrusion side chamber of the hydraulic cylinder for bucket.

  When performing boom lowering, arm dumping, and bucket dumping operations, the boom hydraulic valve, the arm hydraulic cylinder, the arm hydraulic cylinder, the boom control valve, the arm control valve, the bucket control valve, While supplying pressure oil to the rod pull-in side chamber of the bucket hydraulic cylinder, the pressure oil from the remaining two hydraulic pumps is not routed through the common high-pressure piping via the boom control valve, arm control valve, and bucket control valve. , Boom rod retracting side inflow flow rate control valve, arm rod retracting side inflow rate control valve, bucket rod retracting side inflow rate control valve are joined to the flow of pressure oil through the control valve, and the pressure oil is used for boom hydraulic pressure Cylinder, hydraulic cylinder for arm, oil for bucket Supplied to the rod pull-side chamber of the cylinder.

  As described above, in addition to the pressure oil supply route from the two hydraulic pumps through the normal control valve, a pressure oil supply route from the remaining two hydraulic pumps through the common high-pressure piping is not provided. Therefore, it is possible to supply a large amount of pressure oil necessary for the operation of the super large machine to each hydraulic cylinder, and reduce the total number of hoses and the total length of pipes such as steel pipe at that time, thereby reducing the overall pressure loss. be able to.

JP-A-9-328784 (FIG. 9)

JP-A-9-328784 (FIGS. 1 and 2)

  However, there is room for further improvement in the above-described prior art as follows.

  Generally, a hydraulic cylinder has a large volume difference (for example, about 2: 1) between its rod extrusion side chamber and rod drawing side chamber. Therefore, when an actual super large hydraulic excavator is constructed, it is necessary to additionally provide a large flow rate as described above, in order to supply pressure oil to the rod extrusion side chamber. Flow control valve, arm rod extrusion side inflow flow rate control valve, bucket rod extrusion side inflow flow rate control valve, boom rod extrusion side outflow rate control valve for discharging return oil from rod extrusion side chamber, arm rod extrusion side outflow rate control Only a total of six valves and bucket rod extrusion side outflow flow rate control valves are sufficient, and the above six flow rate control valves connected to the rod retracting side chamber are not necessarily essential. If the six flow control valves connected to the rod drawing side chamber can be omitted, the pressure loss due to the flow control valve can be further reduced, and the piping for arranging the flow control valve can be omitted, and the pressure loss can be eliminated. This should further reduce the overall pressure loss. Furthermore, if the number of hydraulic devices such as flow control valves can be reduced, the layout of various pipes and the arrangement of various devices, especially between the hydraulic pump as the hydraulic source and the actuator that receives the pressure oil from this hydraulic source. Should be able to simplify the layout of hydraulic piping.

  In the above-mentioned conventional technology, there is no room for improvement in this sense, in view of this point.

  An object of the present invention is to further reduce the number of flow control valves and the pipe connection length thereof to further reduce the pressure loss as a whole, and to reduce the number of flow control valves, Another object of the present invention is to provide a hydraulic drive device for a construction machine that can simplify the layout of hydraulic piping between actuators that receive pressure oil from the hydraulic source.

  (1) In order to achieve the above object, the present invention provides a first hydraulic pump and a second hydraulic pump driven by a prime mover in a hydraulic drive device for a construction machine that drives and controls a plurality of hydraulic cylinders in the construction machine. A directional flow control valve for switching the pressure oil from the first hydraulic pump to the rod extrusion side chamber and the rod drawing side chamber of the plurality of hydraulic cylinders, and the pressure oil from the second hydraulic pump as one An inflow flow control valve provided in each branch pipe branched from the common pipe and supplied to the rod extrusion side chamber of each hydraulic cylinder, a bypass flow control valve provided in a connection pipe between the common pipe and the tank, and an operation command An input means for inputting a signal and a control amount corresponding to an operation command signal from the input means are calculated, and the inflow flow rate control valve and the bypass flow rate control are calculated based on the control amount. And control means for controlling the valve.

  In the present invention, when constructing a pressure oil supply route that does not involve a control valve for a large flow rate for a very large machine, the pressure oil from the second hydraulic pump is routed from one high-pressure common pipe via a branch pipe. Supply to the rod extrusion side chamber of each corresponding hydraulic cylinder. At this time, the supply flow rate control is performed by controlling the inflow flow rate control valve provided in each branch pipe and the bypass flow rate control valve provided in the connection pipe from the common pipe to the tank with a control amount corresponding to the operation command signal from the input means. This is done by means of control.

  Thus, for example, when supplying pressure oil to the rod extrusion side chamber of each hydraulic cylinder in order to perform boom raising, arm cloud, and bucket cloud operations, each direction flow control valve (control valve) from the first hydraulic pump In addition to the pressure oil supplied via the directional flow control valve, the pressure oil from the second hydraulic pump is changed to the flow of pressure oil via the directional flow control valve via each inflow flow control valve without passing through each directional flow control valve. The pressure oil is supplied to the rod extrusion side chamber of each hydraulic cylinder. The return oil at this time is discharged to the tank only through the path through each directional flow control valve. On the other hand, when supplying pressure oil to the rod retracting side chamber of each hydraulic cylinder to perform, for example, boom lowering, arm dumping, bucket dumping operation, etc., each hydraulic cylinder from the first hydraulic pump via each direction flow control valve Pressure oil is supplied to the rod pull-in side chamber.

  In this way, considering the volume difference between the rod extruding side chamber and the rod retracting side chamber of each hydraulic cylinder, only the rod extruding side inflow flow rate control valve is additionally installed to supply a large flow rate. By omitting the flow control valve, the pressure loss due to the flow control valve can be reduced accordingly, and the piping for arranging the flow control valve can also be omitted, thereby eliminating the pressure loss, thereby further reducing the overall pressure loss can do. Furthermore, by reducing the number of flow control valves, it is possible to simplify the layout of various pipes and the arrangement of various devices, in particular, the layout of the hydraulic pipes between the hydraulic pump as a hydraulic source and the actuator. .

  (2) In order to achieve the above object, the present invention provides a first hydraulic pump and a second hydraulic pressure driven by a prime mover in a hydraulic drive device for a construction machine that drives and controls a plurality of hydraulic cylinders in the construction machine. A pump, a directional flow control valve that supplies pressure oil from the first hydraulic pump to the rod extrusion side chamber and the rod drawing side chamber of the plurality of hydraulic cylinders, and a rod extrusion side chamber of each of the hydraulic cylinders, respectively. An outflow flow rate control valve provided for each return oil merging pipe, an input means for inputting an operation command signal, a control amount corresponding to the operation command signal from the input means is calculated, and the outflow flow rate control valve is calculated by this control amount. And control means for controlling.

  In the present invention, when constructing a pressure oil discharge route not through a control valve for large flow distribution to a super large machine, a return oil confluence pipe is connected to the rod extrusion side chamber of each hydraulic cylinder, and the discharge at this time In the flow rate control, the control means controls the outflow flow rate control valve provided in each return oil merging pipe and the bypass flow rate control valve provided in the connection pipe from the common pipe to the tank with a control amount according to the operation command signal from the input means. Do by controlling.

  Thus, for example, when supplying pressure oil to the rod retracting side chamber of each hydraulic cylinder in order to perform boom lowering, arm dumping, and bucket dumping operations, each direction flow control valve (control valve) from the first hydraulic pump The pressure oil is supplied to the rod retracting side chamber of each hydraulic cylinder through. In addition to the flow discharged from the rod extrusion side chamber of each hydraulic cylinder to the tank through each direction flow control valve, the return oil at this time branches from this flow and flows out without using each direction flow control valve. The flow through the flow control valve and each merging pipe is also discharged to the tank. On the other hand, when supplying pressure oil to the rod extrusion side chamber of each hydraulic cylinder in order to perform, for example, boom raising, arm cloud, bucket cloud operation, etc., return oil from the rod drawing side chamber passes through each direction flow control valve. Discharge to the tank only by route.

  Thus, considering the volume difference between the rod extruding side chamber and the rod retracting side chamber of each hydraulic cylinder, only the rod extruding side outflow flow rate control valve is additionally installed for discharging a large flow rate. By omitting the flow control valve, the pressure loss due to the flow control valve can be reduced accordingly, and the piping for arranging the flow control valve can also be omitted, thereby eliminating the pressure loss, thereby further reducing the overall pressure loss can do. Furthermore, by reducing the number of flow control valves, it is possible to simplify the layout of various pipes and the arrangement of various devices, in particular, the layout of the hydraulic pipes between the hydraulic pump as a hydraulic source and the actuator. .

  (3) In order to achieve the above object, the present invention provides a first hydraulic pump and a second hydraulic pressure driven by a prime mover in a hydraulic drive device for a construction machine that drives and controls a plurality of hydraulic cylinders in the construction machine. A pump, a directional flow control valve that supplies pressure oil from the first hydraulic pump to the rod extrusion side chamber and rod drawing side chamber of the plurality of hydraulic cylinders, and pressure oil from the second hydraulic pump. Inflow flow control valve provided in each branch pipe branched from each common pipe and supplied to the rod extrusion side chamber of each hydraulic cylinder, and outflow flow rate control provided in each return oil merging pipe connected to each branch pipe A valve, a bypass flow rate control valve provided in a connection pipe between the common pipe and the tank, an input means for inputting an operation command signal, and an operation command signal from the input means The control amount is calculated in accordance with, and a control means for controlling the inflow rate control valve, the outlet flow control valve, and the bypass flow control valve by the control amount.

  (4) Further, in order to achieve the above object, the present invention provides a traveling body, a revolving body provided on the upper portion of the traveling body, and a boom rotatably connected to the revolving body. Provided in a construction machine having an arm rotatably connected to the arm and an articulated front work machine including a bucket rotatably connected to the arm, and the boom, the arm, and the bucket, respectively. A boom hydraulic cylinder, an arm hydraulic cylinder, a bucket hydraulic cylinder to be driven, at least one hydraulic pump provided on the revolving structure, one side connected to a discharge side of the at least one hydraulic pump, and the other side to the front A common high-pressure pipe extending to the work machine side and a branch from the common high-pressure pipe, and the opposite side is connected to the rod extrusion side chamber of the boom hydraulic cylinder Pressure oil that is provided in the vicinity of a branch position of the boom branch pipe and the boom branch pipe from the common high-pressure pipe and is supplied from the common high-pressure pipe to the rod extrusion side chamber of the boom hydraulic cylinder. The inflow flow rate control valve for the boom for controlling the flow of the boom and the branching position of the branch pipe for the boom of the common high-pressure pipe branch from the downstream side, and the opposite side is connected to the rod extrusion side chamber of the hydraulic cylinder for the arm A branch pipe for the arm, and a branch of the arm branch pipe in the vicinity of the branch position from the common high-pressure pipe, the pressure oil supplied from the common high-pressure pipe to the rod extrusion side chamber of the arm hydraulic cylinder An inflow flow control valve for the arm that controls the flow and the branch position of the branch pipe for the boom of the common high-pressure pipe branch from the downstream side, and the opposite side is the hydraulic cylinder for the bucket. A branch pipe for the bucket connected to the rod extruding side chamber and a branch position of the branch pipe for the bucket from the common high-pressure pipe, and the rod of the bucket hydraulic cylinder from the common high-pressure pipe A bucket inflow flow rate control valve for controlling the flow of pressure oil supplied to the extrusion side chamber.

  In the present invention, when constructing a pressure oil supply route without a control valve for supplying a large flow rate to a super large machine, it corresponds to the actual arrangement of each actuator and is connected to the discharge side of at least one hydraulic pump. First, branch the boom branch pipe to the boom hydraulic cylinder rod push-out side in the vicinity of the boom hydraulic cylinder from the common high-pressure pipe extended to the front work machine side, then downstream from the branch position The arm branch pipe to the arm hydraulic cylinder rod extrusion side is branched on the side, and the remainder is configured as a bucket branch pipe to the bucket hydraulic cylinder rod extrusion side. A boom inflow flow control valve, an arm inflow flow control valve, and a bucket inflow flow control valve are provided on each of the boom branch pipe, the arm branch pipe, and the bucket branch pipe. Controls the flow of pressure oil to the hydraulic cylinder.

  As a result, when supplying pressure oil to the rod extrusion side chamber of each hydraulic cylinder in order to perform boom raising, arm cloud, and bucket cloud operations, the normal cylinder is connected to the rod extrusion side chamber of each hydraulic cylinder via each control valve. In addition to the pressure oil supply, the pressure oil from at least one hydraulic pump is joined to the pressure oil flow via the control valve via each inflow flow rate control valve without passing through each control valve, and the pressure oil is Supply to the rod extrusion side chamber of each hydraulic cylinder. The return oil at this time is discharged to the tank only through the path through each control valve. On the other hand, for example, when supplying pressure oil to the rod retracting side chamber of each hydraulic cylinder in order to perform boom lowering, arm dumping, bucket dumping operation, etc., the rod retracting side chamber of each hydraulic cylinder via each control valve from the hydraulic pump Supply pressure oil to

  In this way, considering the volume difference between the rod extruding side chamber and the rod retracting side chamber of each hydraulic cylinder, only the rod extruding side inflow flow rate control valve is additionally installed to supply a large flow rate. By omitting the flow control valve, the pressure loss due to the flow control valve can be reduced accordingly, and the piping for arranging the flow control valve can also be omitted, thereby eliminating the pressure loss, thereby further reducing the overall pressure loss can do. Furthermore, by reducing the number of flow control valves, it is possible to simplify the layout of various pipes and the arrangement of various devices, in particular, the layout of the hydraulic pipes between the hydraulic pump as a hydraulic source and the actuator. .

(5) In the above (4), preferably, all inflow flow rate control valves are centrally arranged in one control valve device.

(6) In the above (4), preferably, the boom return oil merge branched from the boom hydraulic cylinder side from the boom inflow flow control valve in the boom branch pipe and connected to the hydraulic tank on the opposite side. Boom outflow flow rate control for controlling the flow of pressure oil provided from the boom hydraulic cylinder to the hydraulic tank provided in the vicinity of the branch position of the pipe and the boom return oil merge pipe from the boom branch pipe A return oil merging pipe for an arm branched from the arm hydraulic cylinder side of the arm branch pipe in the arm branch pipe and connected to the hydraulic tank on the opposite side, and the return oil merging pipe for the arm Of the hydraulic oil that is provided near the branch position from the arm branch pipe and that is discharged from the arm hydraulic cylinder to the hydraulic tank. An arm outflow flow rate control valve for controlling this; a bucket return oil confluence piping branched from the bucket hydraulic cylinder side from the bucket inflow flow rate control valve in the bucket branch piping and connected to the hydraulic tank on the opposite side And a bucket outflow flow control valve for controlling the flow of pressure oil discharged from the bucket hydraulic cylinder to the hydraulic tank, provided near the branch position of the bucket return oil merging pipe from the bucket branch pipe. And at least one of the three sets.

  As a result, when a boom lowering, arm dumping, bucket dumping operation is performed, a part of the large flow rate return oil from the rod extruding side chamber when pressure oil is supplied to the rod drawing side chamber of each hydraulic cylinder via the control valve. Since it can be discharged to the hydraulic tank via each outflow flow rate control valve without going through the control valve, the smooth operation of the front work machine can be performed reliably.

(7) In the above (6), more preferably, all the inflow flow rate control valves and the outflow flow rate control valves are collectively disposed in one control valve device.

(8) In the above (5) or (7), and preferably, the one control valve device is connected to the front.

It is provided at the top of the boom.
(9) In any one of the above (1) to (8), and preferably, the branch pipe supplied to the rod extrusion side chamber of each hydraulic cylinder is provided with a check valve.

(10) In any one of the above (1) to (9), and preferably, at least one of the inflow flow rate control valve, the outflow flow rate control valve, and the bypass flow rate control valve is configured by a seat valve.

(11) In the above (10), more preferably, the seat valve is arranged so that its axis is in a substantially horizontal direction.

  As a result, even if the front work machine performs a rotation operation, the operation direction is a direction orthogonal to the axis, so that it is possible to prevent the rotation operation from affecting the opening / closing operation of the seat valve itself, and a smooth and reliable valve. Operation can be secured.

  According to the present invention, the number of flow control valves and their pipe connection lengths can be further reduced to further reduce the pressure loss as a whole, and thereby the hydraulic pipe between the hydraulic source and the actuator can be reduced. The layout can be simplified.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  A first embodiment of the present invention will be described with reference to FIGS. This embodiment is an embodiment in the case where the present invention is applied to a so-called backhoe type ultra-large hydraulic excavator of the own weight 70 t class, for example.

  FIG. 1 is a hydraulic circuit diagram showing the overall configuration of the hydraulic drive apparatus according to the present embodiment together with its control apparatus. In FIG. 1, this hydraulic drive unit includes hydraulic pumps 1a and 1b driven by an engine (prime mover) 4a, and hydraulic pumps 3a and 3b driven by the engine 4b (however, the engines 4a and 4b and the hydraulic pumps 1a and 1b, 3a and 3b are not limited to this, and may be set as appropriate in consideration of horsepower distribution, etc.), and hydraulic cylinders 5a for booms supplied with oil discharged from these hydraulic pumps 1a, 1b, 3a and 3b , 5b, a hydraulic cylinder for arm 6, a hydraulic cylinder for bucket 7, and a hydraulic tank 2.

The hydraulic pump 1a includes boom hydraulic cylinders 5a and 5b, an arm hydraulic cylinder 6 and a bucket via a first boom control valve 10c, a first arm control valve 10b and a first bucket control valve 10a, respectively. The hydraulic pump 1b connected to the hydraulic cylinder 7 is connected to the boom hydraulic cylinders 5a and 5b and the arm via the second boom control valve 10d, the second arm control valve 10e, and the second bucket control valve 10f, respectively. It is connected to the hydraulic cylinder 6 and the bucket hydraulic cylinder 7. These control valves 10 a to 10 f constitute a control valve group 10.
The rod extrusion side chambers (bottom side oil chambers) 5aA, 5bA of the boom hydraulic cylinders 5a, 5b and the first and second boom control valves 10c, 10d are connected by a main line 105, and the boom hydraulic cylinder 5a is connected. , 5b rod drawing side chambers (rod side oil chambers) 5aB, 5bB and the first and second boom control valves 10c, 10d are connected by a main pipeline 115. Further, the rod extrusion side chamber 6A of the arm hydraulic cylinder 6 and the first and second arm control valves 10b and 10e are connected by a main pipe 106, the rod drawing side chamber 6B of the arm hydraulic cylinder 6 and the first The first and second arm control valves 10 b and 10 e are connected by a main pipe line 116. Further, the rod extrusion side chamber 7A of the bucket hydraulic cylinder 7 and the first and second bucket control valves 10a and 10f are connected by a main pipe 107, and the rod drawing side chamber 7B of the bucket hydraulic cylinder 7 and the first The second bucket control valves 10a and 10f are connected by a main pipe line 117.

  On the other hand, the hydraulic pumps 3a and 3b are connected to the discharge pipe 102 through which the pressure oil discharged from the hydraulic pumps 3a and 3b is guided, and one side (the left side in the figure) is connected to the discharge pipe 102, and the front working machine 14 ( The supply line 100, which is a common high-pressure pipe extended to the side described later), and the branch lines 150A, 150B, 150C connected to be branched from the other side of the supply line 100, respectively, Are connected to the main pipelines 105, 106, and 107.

  Of the branch pipes 150A, 150B, and 150C, the branch pipe 150A as a branch pipe for the boom is branched from the most upstream portion of the supply pipe 100 (in the branch pipes 150A to 150C). . Further, the branch pipe 150B serving as the branch pipe for the arm is branched from a part of the supply pipe 100 downstream from the branch position of the branch pipe 150A for the boom. As a result, the remaining branch pipe 150C as the branch pipe for the bucket is also branched from the branch position of the boom branch pipe 150A in the supply pipe 100 from the downstream side.

  The branch pipes 150A, 150B, and 150C are connected to the boom hydraulic cylinder rod extrusion side chambers 5aA and 5bA, the arm hydraulic cylinder rod extrusion side chamber 6A, and the bucket hydraulic cylinder rod extrusion side chamber 7A from the hydraulic pumps 3a and 3b. For example, an inflow flow rate control valve 201 for a boom including an electromagnetic proportional valve with a pressure compensation function, an inflow flow rate control valve 202 for an arm, each of which includes variable throttles 201A, 202A, and 203A that control the flow of pressure oil to a desired throttle amount, Bucket inflow flow rate control valves 203 are respectively provided. At this time, the inflow flow rate control valve 201 for the boom is disposed in the vicinity of the branch position D1 where the aforementioned branch line 150A branches from the supply line 100, and the inflow flow rate control valve 202 for the arm and the inflow flow rate control for the bucket. The valve 203 is disposed in the vicinity of the branch position D2 where the branch pipelines 150B and 150C branch from the supply pipeline 100.

  Then, on the side of the hydraulic cylinders 5a, 5b, 6 and 7 from the inflow flow rate control valves 201, 202 and 203, the hydraulic cylinder rod push-out side chambers 5aA and 5bA and the arm hydraulic cylinder rod push-outs from the hydraulic pumps 3a and 3b. Non-return valves 151A, 151B, and 151C that allow the flow of pressure oil to the side chamber 6A and the bucket hydraulic cylinder rod extrusion side chamber 7A and block the reverse flow are provided.

  The hydraulic tank 2 includes a tank pipe 103 that guides return oil to the hydraulic tank 2, a low-pressure discharge pipe (return oil merging pipe) 101 having one side (left side in the figure) connected to the tank pipe 103. , Branch pipes 152A (boom return oil merging pipes), branch pipes 152B (arm return oil merging pipes), 152C (bucket return oil merging pipes) connected to branch from the other side of the discharge pipe 101, respectively. The hydraulic cylinders 5a, 5b for the boom and the hydraulic cylinder 6 for the arm from the inflow flow control valves 201, 202, 203 and the check valves 151A, 151B, 151C of the branch pipes 150A, 150B, 150C, respectively. And the bucket hydraulic cylinder 7 side are branched and connected (may be directly connected to the main pipelines 106 and 107).

  In these branch pipes 152A, 152B and 152C, the flow of pressure oil from the hydraulic cylinder rod extrusion side chambers 5aA and 5bA for the boom, the hydraulic cylinder rod extrusion side chamber 6A for the arm, and the hydraulic cylinder rod extrusion side chamber 7A for the bucket to the hydraulic tank 2 The boom outflow flow rate control valve 211, the arm outflow flow rate control valve 212, and the bucket outflow flow rate control valve 213, each comprising, for example, an electromagnetic proportional valve, are provided with variable throttles 211A, 212A, and 213A, respectively, for controlling the desired throttle amount. Is provided.

  At this time, the boom outflow flow rate control valve 211 is disposed in the vicinity of the branch position E1 where the branch conduit 152A branches from the discharge conduit 101 (also in the vicinity of the branch position F1 branched and connected to the branch conduit 150A). The arm outflow flow rate control valve 212 is disposed in the vicinity of the branch position E2 where the branch pipe line 152B branches from the discharge pipe 101 (also in the vicinity of the branch position F2 branched and connected to the branch pipe 150B). The bucket outflow flow rate control valve 213 is provided in the vicinity of the branch position E2 (which is also in the vicinity of the branch position F3 branched and connected to the branch pipe 150C) where the branch pipe 152C branches from the discharge pipe 101. It is arranged.

  The three inflow flow control valves 201, 202, 203, the three check valves 151 A, 151 B, 151 C and the three outflow flow control valves 211, 212, 213 as described above are provided on the upper surface (rear surface) of the boom 75. A single control valve device 190 (see FIG. 2 described later) is centrally arranged in a concentrated manner.

Further, a pipe 104 branches from the supply pipe 100 (or the discharge pipe 102), and a desired amount of the pressure oil discharged from the hydraulic pumps 3a and 3b is supplied to the pipe 104. There is provided a bypass flow rate control valve 204 comprising an electromagnetic proportional valve having a pressure compensation function, for example, which is supplied to the supply line 100 via the variable throttle 204A and returns the rest to the hydraulic tank 2 via the tank line 103. A relief valve 205 is provided between the discharge pipe line 102 and the tank pipe line 103 for defining the maximum pressure of the supply pipe line 100 that is a high-pressure line.
The hydraulic pumps 1a, 1b, 3a, 3b, the control valve group 10, the discharge conduit 102, the tank conduit 103, the conduit 104, the bypass flow control valve 204, the relief valve 205, etc. are shown in FIG. The hydraulic cylinders 5a, 5b, 6, and 7, the supply pipe line 100, the discharge pipe line 101, the branch pipe lines 150A to C and 152A to C, and the inflow flow rate control valves 201, 202, and 203 are provided. The check valves 151A to 151C and the outflow flow rate control valves 211, 212, and 213 are provided in the front work machine 14 (see also FIG. 2).

  In the configuration shown in FIG. 1, the pipe lines 100, 102, 150A to C, 105 to 107, 115 to 117, etc., which are high-pressure lines, are each composed of, for example, a plurality of hoses (or steel pipes). . The pipe lines 101, 103, 152A to C, etc., which are other low-pressure lines, can be replaced by a single large hose (or steel pipe) instead of a plurality of hoses (or steel pipes).

  FIG. 2 is a side view showing the overall structure of a hydraulic excavator that is a subject to be driven by the hydraulic drive apparatus as described above. In FIG. 2, this hydraulic excavator is of a so-called backhoe type (backhoe type), and is provided on a traveling device (lower traveling body) 79 and an upper portion of the traveling device 79 via a swivel bearing 78. A vehicle body (swivel body) 13, an articulated front work machine 14 connected to the vehicle body 13 so as to be pivotable in the vertical direction (a boom 75 pivotally connected to the vehicle body 13, An arm 76 that is movably connected, and a bucket 77) that is rotatably connected to the arm 76 so that the opening portion faces rearward in a grounded state.

  The boom hydraulic cylinders 5a and 5b, the arm hydraulic cylinder 6, and the bucket hydraulic cylinder 7 described above are mounted on the boom 75, the arm 76, and the bucket 77 as shown in the figure, and extend (or contract), respectively. ) The boom is raised (boom lowered), the arm cloud (arm dump), and the bucket cloud (bucket dump) are performed.

  Further, the upper swing body 13 is swung with respect to the lower travel body (travel device) 79 via the swivel bearing 78 by a swing hydraulic motor (not shown) provided therein. The traveling device 79 is provided with left and right traveling hydraulic motors 79b for driving the left and right endless track tracks 79a, respectively.

  Returning to FIG. 1, a controller 31 is provided as a control device of the hydraulic drive device. The controller 31 receives operation signals output from operation levers (input means) 32 and 33 provided in the driver's seat 13A of the vehicle body 13, and controls the control valves 10a to 10f, the inflow flow rate control valves 201 to 203, and the outflow rate control. Command signals are output to the valves 211 to 213 and the bypass flow rate control valve 204. The operation levers 32 and 33 are moved in two directions orthogonal to each other. For example, an operation signal for turning and an operation signal for an arm are output by operating the operation lever 32 in each direction, The operation signal for the boom and the operation signal for the bucket are output by the operation in each direction.

  FIG. 3 shows an inflow which is a main part of the present embodiment, other than the general control function for controlling the control valves 10a to 10f in response to the operation signals of the operation levers 32 and 33, among the detailed functions of the controller 31. It is a functional block diagram showing the control function with respect to the flow control valves 201-203, the outflow flow control valves 211-213, and the bypass flow control valve 204. As shown in FIG. 3, the controller 31 includes a drive signal calculator 231 for the boom inflow rate control valve 201, a drive signal calculator 232 for the arm inflow rate control valve 202, and a bucket inflow rate control valve 203. A drive signal calculator 233, a drive signal calculator 241 for the boom outlet flow rate control valve 211, a drive signal calculator 242 for the arm outlet flow rate control valve 212, and a drive signal calculator 243 for the bucket outlet flow rate control valve 213. And a drive signal calculator 234 for the bypass flow rate control valve 204 and a maximum value selector 235.

  The drive signal calculators 231, 232, 233, 241, 242, 243, 234 receive the operation amount signal X from the corresponding operation levers 32, 33, and correspond to the respective flow control valves 201, 202, 203. , 211, 212, 213, 204 (control signals for solenoid parts 201 B, 202 B, 203 B, 211 B, 212 B, 213 B, 204 B) S are calculated and output to each. At this time, each of the drive signal calculators 231, 232, 233, 241, 242, 243, 234 has an operation pattern (an operation amount signal X of the operation lever and an opening of each valve) corresponding to the operation amount signal X of the operation lever. (Related to the current value of the solenoid drive signal S for opening the area) is stored as a table as shown in FIG. In these operation tables, the operation amount signal X-solenoid drive signal S characteristic is set so that the operation amount signal X has an actuator operation characteristic optimum for the operator according to the characteristic of the corresponding actuator.

  That is, the boom inflow drive signal calculator 231 receives the boom raising operation amount signal X from the operation lever 32, and controls the boom inflow flow control valve 201 based on the illustrated table (drive to the solenoid unit 201B). Signal) S is calculated and output. The arm inflow drive signal calculator 232 receives the arm cloud operation amount signal X from the operation lever 33, and a control signal to the arm inflow flow rate control valve 202 (drive signal to the solenoid unit 202B) based on the illustrated table. S is calculated and output. The bucket inflow drive signal computing unit 233 receives the bucket cloud operation amount signal X from the operation lever 32, and controls the bucket inflow flow rate control valve 203 based on the illustrated table (drive signal to the solenoid unit 203B). S is calculated and output.

  At this time, after the boom raising operation amount signal X, the arm cloud operation amount signal X, and the bucket cloud operation amount signal X from the operation levers 32 and 33 are selected by the maximum value selection unit 235, the bypass drive is performed. The bypass drive signal calculator 234 calculates and outputs a control signal S (drive signal to the solenoid unit 204B) S to the bypass flow rate control valve 204 based on the illustrated table.

  Further, the boom outflow drive signal calculator 241 receives the boom lowering operation amount signal X from the operation lever 32, and controls the boom outflow flow rate control valve 211 based on the illustrated table (drive to the solenoid unit 211B). Signal) S is calculated and output. The am outflow drive signal calculator 242 receives the arm dump operation amount signal X from the operation lever 33, and controls the arm outflow flow rate control valve 212 based on the illustrated table (drive signal to the solenoid unit 212B). S is calculated and output. The bucket outflow drive signal calculator 243 receives the bucket dump operation amount signal X from the operation lever 32, and controls the bucket outflow flow rate control valve 213 based on the illustrated table (drive signal to the solenoid unit 213B). S is calculated and output.

  Next, the operation of the present embodiment having the above configuration will be described.

(1) Boom raising operation When the operator operates the operation lever 32 to raise the boom for excavation, for example, the operation amount signal X is input to the boom control valves 10c and 10d as a boom raising command. The spool can be switched in the corresponding direction. Thereby, the pressure oil from the hydraulic pumps 1a and 1b is supplied to the rod extrusion side chambers 5aA and 5bA of the boom hydraulic cylinders 5a and 5b via the main pipe line 105.

  On the other hand, the boom inflow drive signal calculator 231 calculates the drive signal S of the boom inflow flow rate control valve 201 based on the boom raising operation amount signal X of the operation lever 32 and outputs it to the solenoid unit 201B. At this time, based on other operation signals (boom lowering operation amount signal, arm cloud / dump operation amount signal, bucket cloud / dump operation amount signal), the corresponding solenoid driving is performed by the corresponding driving signal calculators 232, 242, 233, 243. The signal S is calculated. In this case, since no other operation is performed, a reference output (a current value at which the valve does not open. For example, approximately zero) is calculated and output. Then, the maximum value selection unit 235 selects the maximum values of the boom raising operation amount signal X, the arm cloud operation amount signal X, and the bucket cloud operation amount signal X from the operation levers 32 and 33. Since there is no operation state, the bypass drive signal calculator 234 eventually calculates the drive signal S of the bypass flow control valve 204 based on the boom raising operation amount signal X of the operation lever 32 and outputs it to the solenoid unit 204B. Is done. As a result, the bypass flow rate control valve 204 for returning the discharge flow rate from the hydraulic pumps 3a and 3b to the tank 2 is driven to the closed side, and the boom inflow rate control valve 201 is driven to the open side, and the hydraulic pumps 3a and 3b. Is supplied to the rod extrusion side chambers 5aA and 5bA of the boom hydraulic cylinders 5a and 5b via the discharge pipe 102, the supply pipe 100, the branch pipe 150A and the boom inflow flow rate control valve 201.

  As described above, the pressure oil flow rate discharged from the hydraulic pumps 1a and 1b and via the boom control valves 10c and 10d is combined with the pressure oil flow rate discharged from the hydraulic pumps 3a and 3b and via the boom inflow rate control valve 201. Thus, the pump discharge flow rate of the hydraulic pumps 1a, 1b, 3a, 3b flows into the rod extruding side chambers 5aA, 5bA of the boom hydraulic cylinders 5a, 5b.

  At this time, the flow rate of the return oil from the rod retracting side chambers 5aB and 5bB of the boom hydraulic cylinders 5a and 5b is such that the volume ratio of the cylinder rod extruding side chamber: rod retracting side chamber is approximately 2: 1, for example. This is about ½ of the inflow rate into the extrusion side chambers 5aA and 5bA. Therefore, the outflow flow rate is substantially the same as the inflow flow rate from the boom control valves 10c, 10d and is an amount that can be permitted by the control valves 10c, 10d, so that the main pipe line 115 from the rod retracting side chambers 5aB, 5bB, And, it is returned to the tank 2 through meter-out throttles (not shown) of the control valves 10c and 10d.

(2) Boom lowering operation When the operator lowers the boom 32 with the intention of lowering the boom to return to the excavation position after loading the excavated soil, for example, the operation amount signal X is transmitted to the boom control valve 10c, 10d is input as a boom lowering command, and the spool can be switched to the corresponding direction. Thereby, the pressure oil from the hydraulic pumps 1a and 1b is supplied to the rod drawing side chambers 5aB and 5bB of the boom hydraulic cylinders 5a and 5b via the main pipe line 115.

  At this time, due to the volume ratio between the rod extruding side chamber and the rod retracting side chamber described above, the outflow rate from the rod extruding side chambers 5aA and 5bA is approximately twice the inflow rate into the rod drawing side chambers 5aB and 5bB. In the present embodiment, first, a part of the outflow rate (for example, about 1/2) of the main pipe 105 and the control valves 10c and 10d from the rod extruding side chambers 5aA and 5bA is metered out (not shown). To return to the tank 2. On the other hand, the boom outflow drive signal calculator 241 calculates the drive signal S for the boom outflow flow rate control valve 211 based on the boom lowering operation amount signal X of the operation lever 32 and outputs it to the solenoid unit 211B. The drive signal calculator 234 calculates the drive signal S for the bypass flow control valve 204 based on the input manipulated variable signal X (in this case X = 0) and outputs it to the solenoid unit 204B. As a result, the bypass flow rate control valve 204 for returning the discharge flow rate from the hydraulic pumps 3a and 3b to the tank 2 is driven to the open side, and the boom outflow flow rate control valve 211 is driven to the open side. The return oil from the extrusion side chambers 5aA and 5bA is discharged to the tank 2 through the branch conduit 150A, the branch conduit 152A, the boom outflow flow rate control valve 211, the discharge conduit 101, and the tank conduit 103.

(3) Arm crowding operation When the operator operates the arm lever 33 with the intention of arm crowding for excavation, for example, the manipulation amount signal X is input to the arm control valves 10b and 10e as an arm crowding command. The spool can be switched in the corresponding direction. Thus, the pressure oil from the hydraulic pumps 1 a and 1 b is supplied to the rod extrusion side chamber 6 </ b> A of the arm hydraulic cylinder 6 through the main pipeline 106.

  On the other hand, the arm inflow drive signal calculator 232 calculates the drive signal S for the arm inflow flow rate control valve 202 based on the arm cloud operation amount signal X of the operation lever 33 and outputs it to the solenoid unit 202B. In the arm cloud single operation, the bypass drive signal calculator 234 calculates the drive signal S of the bypass flow control valve 204 based on the arm cloud operation amount signal X of the operation lever 33 and outputs it to the solenoid unit 204B. As a result, the bypass flow rate control valve 204 for returning the discharge flow rate from the hydraulic pumps 3a and 3b to the tank 2 is driven to the closed side, and the arm inflow flow rate control valve 202 is driven to the open side, so that the hydraulic pumps 3a and 3b are driven. Is supplied to the rod extrusion side chamber 6A of the arm hydraulic cylinder 6 via the discharge pipe 102, the supply pipe 100, the branch pipe 150B, and the arm inflow flow rate control valve 202.

  As described above, the pressure oil flow rate discharged from the hydraulic pumps 1a and 1b and via the arm control valves 10b and 10e is combined with the pressure oil flow rate discharged from the hydraulic pumps 3a and 3b and via the arm inflow flow rate control valve 202. As a result, the pump discharge flow rate of the hydraulic pumps 1a, 1b, 3a, 3b flows into the rod extrusion side chamber 6A of the arm hydraulic cylinder 6.

  At this time, the outflow flow rate of the return oil from the rod pull-in side chamber 6B of the arm hydraulic cylinder 6 is, for example, about ½ of the inflow rate into the rod extrusion side chamber 6A. Therefore, the outflow rate is almost the same as the inflow rate from the arm control valves 10b and 10e, and is an amount allowable by the control valves 10b and 10e. It is returned to the tank 2 through meter-out throttles (not shown) of the valves 10b and 10e.

(4) Arm dumping operation When the operator performs an arm dumping operation of the operation lever 33 with the intention of arm dumping to load, for example, excavated soil, the operation amount signal X is sent to the arm control valves 10b and 10e as an arm dumping command. Once entered, the spool can be switched to the corresponding direction. As a result, the pressure oil from the hydraulic pumps 1 a and 1 b is supplied to the rod retracting side chamber 6 </ b> B of the arm hydraulic cylinder 6 via the main pipeline 116.

  At this time, due to the volume ratio of the rod extruding side chamber and the rod retracting side chamber described above, the outflow rate from the rod extruding side chamber 6A is approximately twice the inflow rate into the rod retracting side chamber 6B. In the present embodiment, first, a part (for example, about ½) of the outflow flow rate is passed from the rod extrusion side chamber 6B through the main pipe line 106 and meter-out throttles (not shown) of the control valves 10b and 10e. , Returned to the tank 2.

  On the other hand, the arm outflow drive signal calculator 242 calculates the drive signal S of the arm outflow flow rate control valve 212 based on the arm dump operation amount signal X of the operation lever 33 and outputs it to the solenoid unit 212B. Then, the bypass drive signal calculator 234 calculates the drive signal S for the bypass flow control valve 204 based on the input operation amount signal X (in this case, X = 0) and outputs it to the solenoid unit 204B. As a result, the bypass flow rate control valve 204 for returning the discharge flow rate from the hydraulic pumps 3a and 3b to the tank 2 is driven to the open side, and the arm outflow flow rate control valve 212 is driven to the open side, whereby the arm hydraulic cylinder 6 The return oil from the rod extrusion side chamber 6 </ b> A is discharged to the tank via the branch conduit 150 </ b> B, the branch conduit 152 </ b> B, the arm outflow flow rate control valve 212, the discharge conduit 101, and the tank conduit 103.

  Thus, the return oil flow rate from the rod extruding side chamber 6A of the arm hydraulic cylinder 6 is changed to the pressure oil flow rate discharged to the tank via the arm control valves 10b and 10e and to the tank via the arm flow rate control valve 212. It is divided into the pressure oil flow rate to be discharged and discharged to the tank.

(5) Bucket cloud operation For example, when the operator operates the operation lever 32 to perform a bucket cloud operation for excavation, the operation amount signal X is input to the bucket control valves 10a and 10f as a bucket cloud command. The spool can be switched in the corresponding direction. As a result, the pressure oil from the hydraulic pumps 1 a and 1 b is supplied to the rod extruding side chamber 7 </ b> A of the bucket hydraulic cylinder 7 via the main conduit 107.

  On the other hand, the bucket inflow drive signal calculator 233 calculates the drive signal S of the bucket inflow flow rate control valve 203 based on the bucket cloud operation amount signal X of the operation lever 32 and outputs it to the solenoid unit 203B. In the bucket cloud single operation, the bypass drive signal calculator 234 calculates the drive signal S of the bypass flow control valve 204 based on the bucket cloud operation amount signal X of the operation lever 33 and outputs it to the solenoid unit 204B. As a result, the bypass flow rate control valve 204 for returning the discharge flow rate from the hydraulic pumps 3a and 3b to the tank 2 is driven to the closed side, and the bucket inflow rate control valve 203 is driven to the open side, so that the hydraulic pumps 3a and 3b are driven. Is supplied to the rod extrusion side chamber 7A of the bucket hydraulic cylinder 7 through the discharge pipe 102, the supply pipe 100, the branch pipe 150C, and the bucket inflow control valve 203.

  As described above, the pressure oil flow rate discharged from the hydraulic pumps 1a and 1b and passing through the bucket control valves 10a and 10f is combined with the pressure oil flow rate discharged from the hydraulic pumps 3a and 3b and passing through the bucket inflow rate control valve 203. As a result, the pump discharge flow rate of the hydraulic pumps 1 a, 1 b, 3 a, 3 b flows into the rod extrusion side chamber 7 A of the bucket hydraulic cylinder 7. At this time, the return oil from the rod retracting side chamber 6B of the hydraulic cylinder 7 for the bucket is, as in the above (3), the main pipe line 117 and the meter-out restrictors (not shown) of the control valves 10a and 10f from the rod retracting side chamber 7B. And returned to the tank 2.

(6) Bucket dump operation When the operator performs a bucket dump operation of the operation lever 32 with the intention of bucket dumping in order to release the excavated soil on the dump bed, for example, the operation amount signal X is transmitted to the bucket control valve 10a, 10f is input as a bucket dump command, and the spool can be switched to the corresponding direction. As a result, the pressure oil from the hydraulic pumps 1 a and 1 b is supplied to the rod retracting side chamber 7 </ b> B of the bucket hydraulic cylinder 7 through the main pipeline 117.

  At this time, as in the above (4), a part of the outflow flow rate from the rod extrusion side chamber 7A is transferred to the tank from the rod extrusion side chamber 7A via the main pipe 107 and meter-out throttles (not shown) of the control valves 10a and 10f. Return to 2. On the other hand, a drive signal S for the bucket outflow flow rate control valve 213 is calculated by the bucket outflow drive signal calculator 243 based on the bucket dump operation amount signal X of the operation lever 32 and output to the solenoid unit 213B. Then, the bypass drive signal calculator 234 calculates the drive signal S for the bypass flow control valve 204 based on the input manipulated variable signal X (X = 0 in this example) and outputs it to the solenoid unit 204B. . As a result, the bypass flow rate control valve 204 for returning the discharge flow rate from the hydraulic pumps 3a and 3b to the tank 2 is driven to the open side, and the bucket outflow flow rate control valve 213 is driven to the open side, whereby the bucket hydraulic cylinder 7 The return oil from the rod extrusion side chamber 7 </ b> A is discharged to the tank via the branch conduit 150 </ b> C, the branch conduit 152 </ b> C, the bucket outflow flow rate control valve 213, the discharge conduit 101, and the tank conduit 103.

  Thus, the return oil flow rate from the rod extruding side chamber 7A of the bucket hydraulic cylinder 7 is changed to the pressure oil flow rate discharged to the tank via the bucket control valves 10a and 10f and to the tank via the bucket flow rate control valve 213. It is divided into the pressure oil flow rate to be discharged and discharged to the tank.

  In addition, although the above demonstrated taking the case of each operation of boom raising, boom lowering, arm cloud, arm dumping, bucket cloud, and bucket dumping as an example, in the case of compound operation, each of the above was combined at the same time and combined. Needless to say, this kind of control is performed.

  As described above, according to the present embodiment, the hydraulic pump 3a, the hydraulic pump 3a, and the hydraulic pump 3a are configured to supply a large flow rate to the super large machine of the backhoe hydraulic excavator without using the control valves 10a to 10f. First, a boom hydraulic cylinder rod push-out side chamber 5aA is connected to the boom hydraulic cylinder 5a, 5b in the vicinity of the supply pipe 100, which is a common high-pressure pipe connected to the discharge side 3b and extending to the front work machine 14 side. The branch pipe 150A to 5bA is branched, and then the branch pipe 150B to the arm hydraulic cylinder rod extrusion side chamber 6A is branched downstream from the branch position, and the remainder to the bucket hydraulic cylinder rod extrusion side chamber 7A. It is configured as a branch pipe 150C. The branch pipes 150A, 150B, and 150C are each provided with a boom inflow flow rate control valve 201, an arm inflow flow rate control valve 202, and a bucket inflow flow rate control valve 203, and are connected to the hydraulic cylinders 5a and 5b from the supply line 100. , 6 and 7 to control the flow of pressure oil.

  When pressure oil is supplied to the rod extruding side chambers 5aA, 5bA, 6A, and 7A of the hydraulic cylinders 5a, 5b, 6, and 7 in order to perform boom raising, arm cloud, and bucket cloud operations, each normal control is performed. In addition to the pressure oil supply to the rod extrusion side chambers 5aA, 5bA, 6A, and 7A of the hydraulic cylinders 5a, 5b, 6, and 7 through the valves 10a to f, the pressure oil from the hydraulic pumps 3a and 3b is supplied to the control valves. The pressure oil flows through the control valves 10a-f via the inflow flow control valves 201-203 without passing through 10a-f, and the pressure oil is connected to the rods of the hydraulic cylinders 5a, 5b, 6, 7 It supplies to extrusion side chamber 5aA, 5bA, 6A, 7A. The return oil at this time is discharged to the tank only through the path through each control valve 10a-f. On the other hand, when supplying pressure oil to the rod retracting side chambers of the hydraulic cylinders 5a, 5b, 6, 7 for performing boom lowering, arm dumping, bucket dumping operation, etc., the control valves are supplied from the hydraulic pumps 1a, 1b. Pressure oil is supplied to the rod drawing side chambers 5aB, 5bB, 6B, and 7B of the hydraulic cylinders 5a, 5b, 6 and 7 through 10a to f.

  In this way, a large flow rate supply is made in consideration of the volume difference between the rod extrusion side chambers 5aA, 5bA, 6A, 7A and the rod drawing side chambers 5aB, 5bB, 6B, 7B of the respective hydraulic cylinders 5a, 5b, 6, 7. For this purpose, only the inflow flow rate control valves 201, 202, 203 of the branch pipes 150A to 150C on the rod extruding side are added, and the inflow flow rate control valve on the rod drawing side is omitted. The pressure loss can be reduced, the piping for arranging the flow control valve can be omitted, and the pressure loss can be eliminated, whereby the pressure loss of the entire hydraulic drive device can be further reduced. Furthermore, by reducing the number of flow control valves, the layout of various pipes and the arrangement of various devices, particularly between the hydraulic pumps 3a and 3b as hydraulic sources and the hydraulic cylinders 5a, 5b, 6, and 7 The hydraulic piping layout can be simplified.

  Further, for example, in addition to the above-described ultra-large hydraulic excavator, there are a small hydraulic excavator having a weight of about 15 t or less, a medium-sized hydraulic excavator having a weight of about 20 t or less, a large hydraulic excavator having a weight of about 25 t to 40 t. Small and medium-sized hydraulic excavators are used for a relatively wide range of applications including ordinary construction sites in Japan. Large excavators and ultra-large excavators are used for large-scale excavation work. Often used for mining minerals in mines. When such a large hydraulic excavator and a super large hydraulic excavator are delivered from a manufacturer in Japan to a foreign customer, they are transported by ship. For this reason, it is not usually transported as a hydraulic excavator that is a finished product. Instead, it is shipped in the form of being divided into related modules (units), landed at the site, and then assembled into a finished product. It is customary. Generally, a hydraulic drive device of a hydraulic excavator is configured by connecting a hydraulic pump, a tank, a control valve, and the like with a metal hydraulic pipe and a flexible material hose. Since the hose is flexible, both ends of the hose can be easily connected and fixed to the base of the connection target part at the time of assembly after landing. On the other hand, the hydraulic piping is welded to the connection object to form an integral structure. However, if welding is to be performed at the time of assembly after landing as described above, the work becomes very complicated and difficult. For this reason, it is preferable to carry out transportation in a state in which a certain range of welding is completed and made into a block before shipping as much as possible to reduce welding work on site. However, in such a blocked state, there is a predetermined transportation restriction when loading or when loading trucks that carry public roads from the manufacturer to the port, so it is necessary to reduce the size of one block as much as possible. .

  In this embodiment, when the inflow flow rate control valve is blocked in order to minimize welding work after loading and landing for foreign customers by omitting the rod drawing side inflow flow rate control valve as described above. In addition, the flow control valve unit can be downsized. Therefore, the predetermined transportation restriction can be easily cleared at the time of loading or when loading a truck for public road transportation from the manufacturer to the port, and there is an effect that the transportability can be improved.

  Further, in the present embodiment, branch pipelines 150A, 150B, and 150C connected to the boom hydraulic cylinder rod extrusion side chambers 5aA and 5bA, the arm hydraulic cylinder rod extrusion side chamber 6A, and the bucket hydraulic cylinder rod extrusion side chamber 7A. Branch lines 152A, 152B, and 152C that further branch to the discharge line 101 are provided, and the outflow flow rate control valves 211, 212, and 213 are arranged in these lines 152A, 152B, and 152C. Accordingly, when the boom lowering, arm dumping, and bucket dumping operations are performed, pressure is applied to the rod retracting side chambers 5aB, 5bB, 6B, and 7B of the hydraulic cylinders 5a, 5b, 6, and 7 through the control valves 10a, 10b, 10e, and 10f. A part of the large flow rate return oil from the rod extruding side chambers 5aA, 5bA, 6A, and 7A when oil is supplied is supplied to each of the outflow flow rate control valves 211, 212, without passing through the control valves 10a, 10b, 10e, 10f. Since it can discharge | emit to the hydraulic tank 2 via 213, the smooth operation | movement of the front work machine 14 can be performed reliably.

  A second embodiment of the present invention will be described with reference to FIGS. This embodiment is an embodiment in which the present invention is applied to a so-called loader type super large hydraulic excavator different from the first embodiment.

  FIG. 4 is a hydraulic circuit diagram showing the overall configuration of the hydraulic drive apparatus according to the present embodiment together with the control apparatus. Components equivalent to those in FIG. 1 are denoted by the same reference numerals, and description thereof will be omitted as appropriate. In FIG. 1, the hydraulic drive apparatus further includes a bucket opening / closing hydraulic cylinder 8 to which oil discharged from the hydraulic pumps 1 a and 1 b is supplied as a hydraulic cylinder. Correspondingly, the hydraulic pump 1a is connected to the bucket opening / closing hydraulic cylinder 8 via the first bucket opening / closing control valve 10g, and the hydraulic pump 1b is connected to the bucket opening / closing via the second bucket opening / closing control valve 10h. The control valves 10g and 10h are connected to the hydraulic cylinder 8 and constitute a control valve group 10 together with the control valves 10a to 10f described above. The rod extrusion side chamber 8A of the bucket opening / closing hydraulic cylinder 8 and the first and second bucket opening / closing control valves 10g, 10h are connected by a main pipe 108, and the rod retracting side chamber 8B of the bucket opening / closing hydraulic cylinder 8 is connected. The first and second bucket opening / closing control valves 10g and 10h are connected by a main line 118.

  FIG. 5 is a side view showing the overall structure of a hydraulic excavator that is a subject to be driven by the hydraulic drive apparatus as described above. Parts equivalent to those in FIG. 2 described above are denoted by the same reference numerals, and description thereof will be omitted as appropriate. In FIG. 5, this hydraulic excavator is of a so-called loader type, and is arranged such that the bucket 77 provided in the multi-joint type front working machine 14 is in a grounded state so that the opening is directed forward. A bucket opening / closing hydraulic cylinder 8 is mounted on a bucket 77 as shown in the figure. The boom hydraulic cylinders 5a and 5b, the arm hydraulic cylinder 6, the bucket hydraulic cylinder 7, and the bucket opening / closing hydraulic cylinder 8 are each extended (or shortened) to raise the boom (or lower the boom) and push the arm (or Arm pulling, bucket cloud (or bucket dumping), and bucket closing (bucket opening = opening bucket opening 77B with respect to bucket base 77A) are performed.

  Of the branch pipes 150A to 150C, the branch pipe 150A as a branch pipe for the boom is branched from the most upstream side of the supply pipe 100 and the remaining branch pipe for the arm, as in the first embodiment. The branch pipe 150B and the branch pipe 150C as a branch pipe for the bucket are branched downstream of the branch position of the branch pipe 150A for the boom in the supply pipe 100.

  Similarly to the first embodiment, the boom inflow rate control valve 201, the arm inflow rate control valve 202, and the bucket inflow rate control valve 203 are disposed in the vicinity of the aforementioned branch positions D1 and D2. Yes. The boom outflow control valve 211, the arm outflow control valve 212, and the bucket outflow control valve 213 are near the branch positions E1, F1, near the branch positions E2, F2, and near the branch positions E2, F3, respectively. It is arranged. These inflow flow control valves 201, 202, 203, check valves 151 A, 151 B, 151 C and outflow flow control valves 211, 212, 213 are included in one control valve device 190 attached to the upper surface (rear surface) of the boom 75. It is centralized and arranged. The supply pipe 100, the discharge pipe 101, the branch pipes 150A to C, 152A to C, the inflow flow control valves 201, 202, and 203, the check valves 151A to C, and the outflow flow control valves 211, 212, and 213 The front working machine 14 is provided.

  Returning to FIG. 4, the controller 31 ′ provided as the control device of the hydraulic drive device inputs the operation signals output from the operation levers 32 and 33 and the separately provided operation lever 34, and controls the control valves 10 a to h, Command signals are output to the inflow flow rate control valves 201, 202, 203, the outflow flow rate control valves 211, 212, 213, and the bypass flow rate control valve 204.

  FIG. 6 shows the main part of the present embodiment other than the general control function for controlling the control valves 10a to 10h in accordance with the operation signals of the operation levers 32, 33 and 34 among the detailed functions of the controller 31 '. 2 is a functional block diagram showing control functions for the inflow flow rate control valves 201, 202, 203, the outflow flow rate control valves 211, 212, 213, and the bypass flow rate control valve 204. FIG. As shown in FIG. 6, the controller 31 ′ drives the drive signal calculator 231 of the boom inflow flow rate control valve 201 and the arm inflow flow rate control valve 202 in the same manner as the controller 31 of the first embodiment. A signal calculator 232, a drive signal calculator 233 for the bucket inflow flow rate control valve 203, a drive signal calculator 241 for the boom outflow rate control valve 211, and a drive signal calculator 242 for the arm outflow rate control valve 212. , A drive signal calculator 243 for the bucket outflow flow rate control valve 213, a drive signal calculator 234 for the bypass flow rate control valve 204, and a maximum value selector 235.

  Here, in the present embodiment, the arm inflow drive signal calculator 232 inputs the arm pushing operation amount signal X from the operation lever 33, and the control signal to the arm inflow flow rate control valve 202 based on the illustrated table. (Drive signal to solenoid 202B) S is calculated and output. Then, after the boom raising operation amount signal X, the arm pushing operation amount signal X, and the bucket cloud operation amount signal X from the operation levers 32 and 33 are selected by the maximum value selection unit 235, the bypass drive signal calculation is performed. The bypass drive signal calculator 234 calculates and outputs the control signal S to the bypass flow rate control valve 204. Further, the arm outflow drive signal calculator 242 receives the arm pulling operation amount signal X from the operation lever 33 and controls the control signal (drive to the solenoid unit 212B) to the arm outflow flow rate control valve 212 based on the illustrated table. Signal) S is calculated and output.

Next, the operation of the present embodiment having the above configuration will be described below.
(1) Boom raising operation (2) Boom lowering operation Since these (1) and (2) are the same as those in the first embodiment, description thereof will be omitted.
(3) Arm pushing operation When the operator pushes the operating lever 33 with the intention of pushing the arm for excavation, for example, the operation amount signal X is input to the arm control valves 10b and 10e as an arm pushing command. The spool can be switched in the corresponding direction. Thus, the pressure oil from the hydraulic pumps 1 a and 1 b is supplied to the rod extrusion side chamber 6 </ b> A of the arm hydraulic cylinder 6 through the main pipeline 106.

  On the other hand, the arm inflow drive signal calculator 232 calculates the drive signal S of the arm inflow flow rate control valve 202 based on the arm pushing operation amount signal X of the operation lever 33 and outputs it to the solenoid unit 202B. In the arm push single operation, the bypass drive signal calculator 234 calculates the drive signal S of the bypass flow control valve 204 based on the arm push operation amount signal X of the operation lever 33 and outputs it to the solenoid unit 204B. As a result, the bypass flow rate control valve 204 for returning the discharge flow rate from the hydraulic pumps 3a and 3b to the tank 2 is driven to the closed side, and the arm inflow flow rate control valve 202 is driven to the open side, so that the hydraulic pumps 3a and 3b are driven. Is supplied to the rod extrusion side chamber 6A of the arm hydraulic cylinder 6 via the discharge pipe 102, the supply pipe 100, the branch pipe 150B, and the arm inflow flow rate control valve 202.

  As described above, the pressure oil flow rate discharged from the hydraulic pumps 1a and 1b and via the arm control valves 10b and 10e is combined with the pressure oil flow rate discharged from the hydraulic pumps 3a and 3b and via the arm inflow flow rate control valve 202. As a result, the pump discharge flow rate of the hydraulic pumps 1a, 1b, 3a, 3b flows into the rod extrusion side chamber 6A of the arm hydraulic cylinder 6.

At this time, the outflow flow rate of the return oil from the rod pull-in side chamber 6B of the arm hydraulic cylinder 6 is, for example, about ½ of the inflow rate into the rod extrusion side chamber 6A. Therefore, the outflow rate is almost the same as the inflow rate from the arm control valves 10b and 10e, and is an amount allowable by the control valves 10b and 10e. It is returned to the tank 2 through meter-out throttles (not shown) of the valves 10b and 10e.
It is returned to the second.

(4) Arm pulling operation When the operator pulls the operating lever 32 with the intention of pulling the arm after earthing, for example, the operation amount signal X is input to the arm control valves 10b and 10e as an arm pulling command. The spool can be switched in the corresponding direction. As a result, the pressure oil from the hydraulic pumps 1 a and 1 b is supplied to the rod retracting side chamber 6 </ b> B of the arm hydraulic cylinder 6 through the main pipeline 116.

  At this time, due to the volume ratio of the rod extruding side chamber and the rod retracting side chamber described above, the outflow rate from the rod extruding side chamber 6A is approximately twice the inflow rate into the rod retracting side chamber 6B. In the present embodiment, first, a part (for example, about ½) of the outflow flow rate is passed from the rod extrusion side chamber 6B through the main pipe line 106 and meter-out throttles (not shown) of the control valves 10b and 10e. , Returned to the tank 2.

  On the other hand, the arm outflow drive signal calculator 242 calculates the drive signal S for the arm outflow flow rate control valve 212 based on the arm pulling operation amount signal X of the operation lever 33 and outputs it to the solenoid unit 212B. Then, the bypass drive signal calculator 234 calculates the drive signal S for the bypass flow control valve 204 based on the input operation amount signal X (in this case, X = 0) and outputs it to the solenoid unit 204B. As a result, the bypass flow rate control valve 204 for returning the discharge flow rate from the hydraulic pumps 3a and 3b to the tank 2 is driven to the open side, and the arm outflow flow rate control valve 212 is driven to the open side, whereby the arm hydraulic cylinder 6 The return oil from the rod extrusion side chamber 6 </ b> A is discharged to the tank via the branch conduit 150 </ b> B, the branch conduit 152 </ b> B, the arm outflow flow rate control valve 212, the discharge conduit 101, and the tank conduit 103.

Thus, the return oil flow rate from the rod extruding side chamber 6A of the arm hydraulic cylinder 6 is changed to the pressure oil flow rate discharged to the tank via the arm control valves 10b and 10e and to the tank via the arm flow rate control valve 212. It is divided into the pressure oil flow rate to be discharged and discharged to the tank.
(5) Bucket cloud operation (6) Bucket dump operation Since these (5) and (6) are also the same as those in the first embodiment, description thereof will be omitted.

  In the case of a loader type hydraulic excavator to which the present embodiment is applied, as a typical operation, first, the front work machine 14 is bent toward the vehicle body 13 side, and then the boom is raised, the arm is pushed, and the bucket is moved. After scooping the sand on the front side of the front work machine into the bucket 77 by the cloud operation, the bucket 77 is lifted high as it is, and the bucket opening part 77B is opened with respect to the bucket base part 77A. Release earth and sand. Thereafter, the boom lowering and arm pulling operations are performed almost simultaneously while performing the bucket closing and bucket dumping operations, and the front working machine 14 is returned to the initial state where it is bent toward the vehicle body 13 side.

  Here, in the above (1) to (6), the case where the boom is raised, the boom is lowered, the arm is pushed, the arm is pulled, the bucket cloud, and the bucket dump are individually operated is described as an example. Needless to say, in the case of combined operation including (1), (1) to (6) are combined at the same time to perform combined control.

  Also according to the present embodiment, as in the first embodiment, the pressure loss due to the flow control valve can be reduced, the piping for arranging the flow control valve can be omitted, and the pressure loss can be eliminated. The pressure loss of the entire drive device can be further reduced. Furthermore, by reducing the number of flow control valves, the layout of various pipes and the arrangement of various devices, particularly between the hydraulic pumps 3a and 3b as hydraulic sources and the hydraulic cylinders 5a, 5b, 6, and 7 The hydraulic piping layout can be simplified.

  A third embodiment of the present invention will be described with reference to FIG.

  FIG. 7 is a hydraulic circuit diagram showing a main configuration of the hydraulic drive device according to the present embodiment. Parts equivalent to those in the first and second embodiments are denoted by the same reference numerals, and description thereof is omitted as appropriate.

  In the first and second embodiments, attention is paid to the boom hydraulic cylinder rod extrusion side chambers 5aA, 5bA, the arm hydraulic cylinder rod extrusion side chamber 6A, and the bucket hydraulic cylinder rod extrusion side chamber 7A having a relatively large volume ratio. The boom inflow flow rate control valve 201, the arm inflow flow rate control valve 202, and the bucket inflow flow rate control valve 203 for controlling the pressure oil supply from the hydraulic pumps 3a, 3b to the rod extrusion side chambers 5aA, 5bA, 6A, 7A. And a boom outflow rate control valve 211, an arm outflow rate control valve 212, and a bucket outflow rate control valve 213 for controlling the pressure oil discharge from the rod extrusion side chambers 5aA, 5bA, 6A, and 7A. It is not necessarily limited to this. That is, when only the pressure oil supply to the boom hydraulic cylinder rod extrusion side chambers 5aA and 5bA, the arm hydraulic cylinder rod extrusion side chamber 6A, and the bucket hydraulic cylinder rod extrusion side chamber 7A is considered, the outflow flow rate control valve 211, 212, 213, etc. (and pipes 101, 152A, 152B, 152C, etc.) are omitted, and only the corresponding boom inflow flow control valve 201, arm inflow flow control valve 202, and bucket inflow flow control valve 203 are provided. It is enough if it is provided.

  This embodiment is an embodiment in which the above technical idea is embodied. In this example, for example, a backhoe type hydraulic excavator as in the first embodiment or a second embodiment is used. The boom inflow flow rate control valve 201 is provided with particular attention paid to the pressure oil supply to the boom hydraulic cylinder extruding side chambers 5aA and 5bA (not shown) in a loader type hydraulic excavator. For example, in the case of the loader type embodiment, the arm inflow flow rate control valve 202 described above may be provided instead of the boom inflow flow rate control valve 201.

  Also in this embodiment, as compared with the case where an inflow flow rate control valve is also provided in the rod drawing side chamber, at least the number of flow rate control valves and the piping related thereto can be reduced or omitted. The original effects of the present invention such as reduction and layout simplification can be obtained.

  A fourth embodiment of the present invention will be described with reference to FIG.

  FIG. 8 is a hydraulic circuit diagram showing a main configuration of the hydraulic drive device according to the present embodiment. Portions equivalent to those in the first to third embodiments are denoted by the same reference numerals, and description thereof is omitted as appropriate.

  Contrary to the third embodiment, inflow flow rate control in the first and second embodiments when only the pressure oil discharge from the rod extrusion side chambers 5aA, 5bA, 6A, and 7A has to be considered. Inflow flow rate control valves 201, 202, and 203 are provided among the valves 201, 202, and 203, as well as the hydraulic pumps 3a and 3b, the prime mover 4b, the pipelines 102, 100, and 104, and the pipelines 150A, 150B, and 150C. It is sufficient to omit the part, the bypass flow control valve 204, the relief valve 205, etc., and provide only the outflow flow control valves 211, 212, and 213.

  This embodiment is an embodiment in which the above technical idea is embodied. In this example, for example, a backhoe type hydraulic excavator as in the first embodiment or a second embodiment is used. The boom outflow flow rate control valve 211 is provided with particular attention paid to the pressure oil discharge from the hydraulic cylinder rod extrusion side chambers 5aA and 5bA (not shown) in a loader type hydraulic excavator. However, the present invention is not limited to this. For example, in the case of the loader type embodiment, the arm outflow flow rate control valve 212 may be provided instead of the boom outflow flow rate control valve 211 described above.

  Also in this embodiment, the number of flow control valves and the piping associated therewith can be reduced / omitted as compared with the case where an outflow flow control valve is also provided in the rod drawing side chamber. The original effects of the present invention such as reduction and layout simplification can be obtained.

  In addition, each flow control valve 201, 202, 203 demonstrated in the said 1st-4th embodiment can also be comprised with a seat valve with comparatively little pressure loss. An example of this configuration will be described with reference to FIGS. FIG. 9 is a diagram extracted from FIG. 1 by taking the flow control valve 202 as an example, and FIG. 10 is a diagram showing the configuration of the seat valve corresponding to the configuration of FIG.

  That is, in FIG. 10, a main valve (seat valve) 603 made of a poppet fitted in the casing 602 is connected to the branch line 150B via the inlet line 621 communicating with the supply line 100 and the check valve. The pressure in the back pressure chamber 604 formed between the seat portion 603A that communicates and blocks the outlet pipe 631, the end surface 603C that receives the pressure of the outlet pipe 631, and the casing 602 that is provided on the opposite side of the end face 603C. Receiving end surface 603B, and a throttle slit 603D communicating the inlet pipe line 621 and the back pressure chamber 604. The casing 602 is formed with a pilot pipe line 605 that allows the back pressure chamber 604 and the outlet pipe line 631 to communicate with each other. On the pilot pipe line 605, for example, a pilot pipe line is transmitted by a command signal 601 from a controller. A control valve (variable throttle unit) 606 for controlling the control pressure, which is a proportional solenoid valve for adjusting the flow rate of 605, is provided.

  In this configuration, the pressure in the inlet pipe 621 is guided into the back pressure chamber 604 via the throttle slit 603D, and the main valve 603 is pressed downward in the figure by this pressure, and the inlet pipe is pushed by the seat portion 603A. The path 621 and the outlet pipe line 631 are blocked. Here, when a desired command signal 601 is given to the solenoid driving unit 606a of the control valve 606 and the control valve 606 is opened, the fluid in the inlet pipe line 621 is the throttle slit 603D, the back pressure chamber 604, the control valve 606, and the pilot. It flows out to the outlet pipe 631 through the pipe 605. Due to this flow, the pressure in the back pressure chamber 604 decreases due to the throttling effect of the throttling slit 603D and the control valve 606, so that the force acting on the end surface 603A and the end surface 603E is greater than the force acting on the end surface 603B. The main valve 603 moves upward in the figure, and the fluid in the inlet pipe 621 flows out to the outlet pipe 631. At this time, if the main valve 603 is excessively lifted, the throttle opening of the throttle slit 603D is increased, whereby the pressure in the back pressure chamber 604 is increased and the main valve 603 is moved downward in the figure.

  In this way, the main valve 603 stays at the throttle opening position of the throttle slit 603D corresponding to the throttle opening degree of the control valve 606. Therefore, based on the command signal 601, the desired inlet pipe line 621 is connected to the outlet pipe pipe. The fluid flow rate to 631 can be controlled.

  Needless to say, each of the flow rate control valves (flow rate control valves that do not require the check valve function) 204, 211, 212, and 213 other than the above can also be configured by the same seat valve as described above.

  At this time, it is preferable that each flow control valve is particularly arranged so that the axis k (see FIG. 10) of the main valve 603 is substantially horizontal. 2 of the first embodiment described above and FIG. 5 of the second embodiment, in the valve device 190 including the flow control valves 201 to 203 and the outflow flow control valves 211 to 213, the axial direction k An example is shown. Such an arrangement has the following effects. That is, in FIGS. 2 and 5, even when the front working machine 14 is rotated in the in-plane direction, if the axial direction k is substantially horizontal as shown, the acceleration due to the rotating operation is increased. Since the direction is perpendicular to the direction of the opening / closing operation of the main valve 603, it is possible to prevent the opening / closing operation from being affected. Therefore, a smooth and reliable opening / closing operation of the main valve 603 can be ensured.

  In the above, a pilot pressure as a direct control pressure is generated in the pilot line 605 by inputting a command signal to the solenoid driving unit 606A of the control valve 606, which is an electromagnetic proportional valve, and switching the control valve 606. Not limited to this. For example, when a relatively large pilot pressure is required to drive the main valve 603 in a large size, a hydraulic pilot type switching valve for generating a secondary pilot pressure is further provided and generated by the control valve 606. The switching valve is switched by the primary pilot pressure to generate a secondary pilot pressure larger than the primary pilot pressure based on the pilot original pressure from the hydraulic power source, and this secondary pilot pressure is led to the main valve 603 side as a control pressure. The main valve 603 may be switched and driven.

  Furthermore, although the said 1st-3rd embodiment is embodiment which applied this invention to the hydraulic excavator, it applies widely to the construction machine provided with the other swivel body, traveling body, and front work machine. be able to.

1 is a hydraulic circuit diagram showing an overall configuration of a hydraulic drive device according to a first embodiment of the present invention together with a control device thereof. It is a side view showing the whole structure of the hydraulic excavator which is a drive object of the hydraulic drive device shown in FIG. It is a functional block diagram showing the control function with respect to the inflow flow rate control valve, the outflow flow rate control valve, and the bypass flow rate control valve among the detailed functions of the controller shown in FIG. It is the hydraulic circuit diagram which showed the whole structure of the hydraulic drive unit by the 2nd Embodiment of this invention with the control apparatus. It is a side view showing the whole structure of the hydraulic excavator which is a drive object of the hydraulic drive device shown in FIG. It is a functional block diagram showing the control function with respect to the inflow flow rate control valve, the outflow flow rate control valve, and the bypass flow rate control valve among the detailed functions of the controller shown in FIG. FIG. 5 is a hydraulic circuit diagram showing a configuration of a hydraulic drive device according to a third embodiment of the present invention. It is the hydraulic circuit figure which showed the structure of the hydraulic drive device by the 4th Embodiment of this invention. It is the figure which extracted and showed one of the flow control valves from FIG. It is explanatory drawing at the time of comprising a flow control valve with a seat valve.

Explanation of symbols

1a, 1b Hydraulic pump 2 Tank 3a, 3b Hydraulic pump,
4a, 4b engine (motor)
5a, 5b Boom hydraulic cylinders 5aA, 5bA Rod extrusion side chambers 5aB, 5bB Rod retraction side chamber 6 Arm hydraulic cylinder 6A Rod extrusion side chamber 6B Rod retraction side chamber 7 Bucket hydraulic cylinder 7A Rod extrusion side chamber 7B Rod retraction side chamber 10a-f Control valve 13 Car body (swivel body)
14 Front working machine 75 Boom 76 Arm 77 Bucket 79 Traveling device (traveling body)
201 Inflow flow control valve for boom 202 Inflow flow control valve for arm 203 Inflow flow control valve for bucket 204 Bypass flow control valve 211 Outflow flow control valve for boom 212 Outflow flow control valve for arm 213 Outflow flow control valve for bucket 603 Main valve (Seat valve)

Claims (11)

In a hydraulic drive device for a construction machine that drives and controls a plurality of hydraulic cylinders in the construction machine,
A first hydraulic pump and a second hydraulic pump driven by a prime mover;
A directional flow control valve for supplying pressure oil from the first hydraulic pump to the rod extrusion side chamber and the rod drawing side chamber of the plurality of hydraulic cylinders;
An inflow flow rate control valve provided in each branch pipe for branching the pressure oil from the second hydraulic pump from one common pipe to the rod extrusion side chamber of each hydraulic cylinder;
A bypass flow rate control valve provided in a connection pipe between the common pipe and the tank;
An input means for inputting an operation command signal;
A hydraulic pressure for a construction machine, comprising: a control unit that calculates a control amount according to an operation command signal from the input unit and controls the inflow flow rate control valve and the bypass flow rate control valve based on the control amount. Drive device. In a hydraulic drive device for a construction machine that drives and controls a plurality of hydraulic cylinders in the construction machine,
A first hydraulic pump and a second hydraulic pump driven by a prime mover;
A directional flow control valve for supplying pressure oil from the first hydraulic pump to the rod extrusion side chamber and the rod drawing side chamber of the plurality of hydraulic cylinders;
An outflow rate control valve provided in each return oil merging pipe connected to the rod extrusion side chamber of each hydraulic cylinder;
An input means for inputting an operation command signal;
A hydraulic drive device for a construction machine, comprising: a control unit that calculates a control amount according to an operation command signal from the input unit and controls the outflow flow rate control valve based on the control amount. In a hydraulic drive device for a construction machine that drives and controls a plurality of hydraulic cylinders in the construction machine,
A first hydraulic pump and a second hydraulic pump driven by a prime mover;
A directional flow control valve for supplying pressure oil from the first hydraulic pump to the rod extrusion side chamber and the rod drawing side chamber of the plurality of hydraulic cylinders;
An inflow flow rate control valve provided in each branch pipe for branching the pressure oil from the second hydraulic pump from one common pipe to the rod extrusion side chamber of each hydraulic cylinder;
An outflow rate control valve provided in each return oil merged pipe connected to each branch pipe;
A bypass flow rate control valve provided in a connection pipe between the common pipe and the tank;
An input means for inputting an operation command signal;
A control unit that calculates a control amount according to an operation command signal from the input unit and controls the inflow flow rate control valve, the outflow flow rate control valve, and the bypass flow rate control valve by the control amount. A hydraulic drive device for a construction machine. A traveling body, a revolving body provided on the upper part of the traveling body so as to be able to turn, a boom rotatably connected to the revolving body, an arm rotatably connected to the boom, and a turn to the arm Provided in a construction machine having an articulated front work machine composed of buckets connected to each other,
A boom hydraulic cylinder, an arm hydraulic cylinder, and a bucket hydraulic cylinder that respectively drive the boom, the arm, and the bucket;
At least one hydraulic pump provided in the revolving structure;
A common high-pressure pipe having one side connected to the discharge side of the at least one hydraulic pump and the other side extending to the front work machine side;
Branching from this common high-pressure pipe, the other side is connected to the rod extrusion side chamber of the boom hydraulic cylinder, boom branching pipe,
The boom branch pipe is provided in the vicinity of the branch position from the common high-pressure pipe, and controls the flow of pressure oil supplied from the common high-pressure pipe to the rod extrusion side chamber of the boom hydraulic cylinder. A flow control valve;
A branch pipe for the arm that branches from the downstream side of the branch position of the branch pipe for the boom of the common high-pressure pipe, and the opposite side is connected to the rod extrusion side chamber of the hydraulic cylinder for the arm;
This arm branch pipe is provided in the vicinity of the branch position from the common high pressure pipe and controls the flow of pressure oil supplied from the common high pressure pipe to the rod extrusion side chamber of the arm hydraulic cylinder. A flow control valve;
A branch branch pipe for the bucket that branches from the downstream side of the branch position of the branch pipe for the boom of the common high-pressure pipe, and the opposite side is connected to the rod extrusion side chamber of the hydraulic cylinder for bucket;
The bucket branch pipe is provided near the branch position from the common high-pressure pipe, and controls the flow of pressure oil supplied from the common high-pressure pipe to the rod extrusion side chamber of the bucket hydraulic cylinder. A hydraulic drive device for a construction machine comprising a flow control valve. The hydraulic drive device for a construction machine according to claim 4,
A hydraulic drive device for a construction machine, characterized in that all inflow flow rate control valves are collectively arranged in one control valve device. The hydraulic drive device for a construction machine according to claim 4,
The boom return oil merging pipe branched from the boom hydraulic cylinder side from the boom inflow flow control valve in the boom branch pipe and connected to the hydraulic tank on the opposite side, and the boom of the boom return oil merging pipe An outflow flow control valve for a boom that is provided in the vicinity of a branch position from the branch pipe for use and controls the flow of pressure oil discharged from the hydraulic cylinder for the boom to the hydraulic tank;
The return oil merging pipe for the arm branched from the arm hydraulic cylinder side from the arm inflow flow rate control valve in the arm branch pipe and connected to the hydraulic tank on the opposite side, and the arm of the return oil merging pipe for the arm An arm outflow flow rate control valve that is provided in the vicinity of a branch position from the branch piping for the arm and that controls the flow of pressure oil discharged from the arm hydraulic cylinder to the hydraulic tank;
The bucket return oil merging pipe branched from the bucket inflow flow rate control valve in the bucket branch pipe from the bucket hydraulic cylinder side and connected to the hydraulic tank on the opposite side, and the bucket of the bucket return oil merging pipe Out of three sets of: a bucket outflow flow rate control valve that is provided in the vicinity of a branch position from a branch pipe for use and that controls the flow of pressure oil discharged from the bucket hydraulic cylinder to the hydraulic tank;
A hydraulic drive device for a construction machine comprising at least one set. The hydraulic drive device for a construction machine according to claim 6,
A hydraulic drive device for a construction machine, characterized in that all inflow flow rate control valves and outflow flow rate control valves are collectively arranged in one control valve device. The hydraulic drive device for a construction machine according to claim 5 or 7,
A hydraulic drive device for a construction machine, wherein the one control valve device is provided on an upper portion of the boom. The hydraulic drive device for a construction machine according to any one of claims 1 to 8,
A hydraulic drive device for a construction machine, characterized in that a check pipe is provided in a branch pipe supplied to a rod extruding side chamber of each hydraulic cylinder. The hydraulic drive device for a construction machine according to any one of claims 1 to 9,
A hydraulic drive device for a construction machine, wherein at least one of the inflow flow rate control valve, the outflow flow rate control valve, and the bypass flow rate control valve is a seat valve. The hydraulic drive device for a construction machine according to claim 10,
The hydraulic drive device for a construction machine, wherein the seat valve is disposed so that an axis thereof is substantially horizontal.

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