JP4606004B2 - Hydraulic drive unit for construction machinery - Google Patents

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 relates to a traveling body, a revolving body that constitutes a vehicle body that is turnably provided on an upper portion of the traveling body, and a revolving body that is connected to the revolving body so as to be able to move up and down. In a hydraulic drive device for a construction machine provided in a construction machine having an articulated front work machine including an arm and a bucket, a first hydraulic pump and a second hydraulic pump driven by a prime mover, and the prime mover A third hydraulic pump to be driven, and a hydraulic cylinder for a boom that is supplied with pressure oil discharged from the first hydraulic pump , the second hydraulic pump, and the third hydraulic pump and drives the boom, the arm, and the bucket, respectively. , A plurality of hydraulic cylinders including a hydraulic cylinder for arm and a hydraulic cylinder for bucket, and pressure supplied from the first hydraulic pump to the plurality of hydraulic cylinders Controls the flow of each supply outlet flow rate of the hydraulic fluid discharged from said plurality of hydraulic cylinders and a plurality of first directional flow control valve back to the tank, respectively, from the second hydraulic pump to said plurality of hydraulic cylinders A plurality of second directional flow control valves for controlling the flow of the pressurized oil and returning the flow rate of the pressure oil discharged from the plurality of hydraulic cylinders to the tank, respectively, and one side of which is discharged from the third hydraulic pump A common high-pressure pipe connected to the other side and extending to the front work machine side, and a branch from the common high-pressure pipe on the front work machine side, and the opposite side to the rod extrusion side chamber of the boom hydraulic cylinder The connected boom branch pipe and the boom branch pipe are provided in the vicinity of the branch position from the common high-pressure pipe. A boom inlet flow control valve for controlling a flow of pressure oil supplied to the rod extrusion side chamber of the boom hydraulic cylinder, the branch position of the branch pipe for the boom of the common high-pressure pipe in the front work machine side The arm branch pipe branched from the downstream side and the opposite side connected to the rod extrusion side chamber of the arm hydraulic cylinder, and provided near the branch position from the common high-pressure pipe of the arm branch pipe, An arm inflow flow rate control valve for controlling the flow of pressure oil supplied from a common high pressure pipe to the rod extrusion side chamber of the arm hydraulic cylinder, and the boom branch of the common high pressure pipe on the front work machine side A branch pipe for the bucket that branches from the downstream side from the branch position of the pipe, and the opposite side is connected to the rod extrusion side chamber of the bucket hydraulic cylinder; A bucket inflow flow rate that is provided in the vicinity of a branch position of the branch branch pipe from the common high-pressure pipe and that controls the flow of pressure oil supplied from the common high-pressure pipe to the rod extrusion side chamber of the bucket hydraulic cylinder. And a control valve, and during boom raising operation for extending the boom hydraulic cylinder, pressure oil from the first hydraulic pump and pressure oil from the second hydraulic pump are supplied to the rod extrusion side chamber of the boom hydraulic cylinder. Each of the plurality of first and second directional flow control valves is supplied through a corresponding one, and the pressure oil from the third hydraulic pump is supplied through the boom inflow flow control valve. During the boom lowering operation for shortening the hydraulic cylinder, the pressure oil from the first hydraulic pump and the second hydraulic pump are brought into the rod retracting side chamber of the boom hydraulic cylinder. During the operation of supplying only oil through the corresponding ones of the plurality of first and second directional flow control valves and extending the arm hydraulic cylinder, the rod extruding side chamber of the arm hydraulic cylinder has the first Pressure oil from one hydraulic pump and pressure oil from the second hydraulic pump are supplied through corresponding ones of the plurality of first and second directional flow control valves, respectively, and pressure from the third hydraulic pump In the operation of supplying oil via the arm inflow flow rate control valve and contracting the arm hydraulic cylinder, the pressure oil from the first hydraulic pump and the second oil are supplied to the rod retracting side chamber of the arm hydraulic cylinder. In the operation of supplying only the hydraulic oil from the hydraulic pump through the corresponding ones of the plurality of first and second directional flow control valves respectively, and extending the bucket hydraulic cylinder, Pressure oil from the first hydraulic pump and pressure oil from the second hydraulic pump are supplied to the rod extruding side chamber of the hydraulic cylinder for the ket through corresponding ones of the plurality of first and second directional flow control valves, respectively. In addition, when the pressure oil from the third hydraulic pump is supplied via the bucket inflow flow control valve and the bucket hydraulic cylinder is contracted, the rod retracting side chamber of the bucket hydraulic cylinder has the second Only the pressure oil from one hydraulic pump and the pressure oil from the second hydraulic pump are supplied through corresponding ones of the plurality of first and second directional flow control valves, respectively, and the plurality of first A directional flow control valve and the plurality of second directional flow control valves are arranged on the vehicle body side, and all of the boom inflow flow control valve, the arm inflow flow control valve, and the bucket inflow flow control valve The inflow flow rate control valves are collectively arranged in one control valve device, and the one control valve device is arranged in the upper part of the boom.

  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. .
In addition, when a large hydraulic excavator or a super large hydraulic excavator is delivered from a Japanese manufacturer to a foreign customer, it is 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 the present invention, all the inflow flow rate control valves of the inflow flow rate control valve for the boom, the inflow flow rate control valve for the arm, and the inflow flow rate control valve for the bucket are collectively arranged in one control valve device, and the one control is performed. Place the valve device on top of the boom. Thus, by making the three inflow flow control valves into one block, the welding work after loading and landing for foreign customers can be reduced as much as possible. Further, by omitting the rod pull-in side inflow flow control valve as described above, when making three inflow flow control valves into one block in order to minimize welding work after loading and landing for foreign customers, The block can be reduced in size. Therefore, a 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 the transportability can be improved.

(2) In the above (1), good Mashiku returns boom opposite side connected to the hydraulic tank is branched from the boom hydraulic cylinder side with respect to the boom inlet flow control valve in the branch pipe for the boom oil Boom outflow rate for controlling the flow of pressure oil discharged from the boom hydraulic cylinder to the hydraulic tank provided in the vicinity of a branch position of the boom return oil junction pipe from the boom branch pipe. A control valve; an arm return oil merging pipe branched from the arm hydraulic cylinder side from the arm inflow flow rate control valve in the arm branch pipe and connected to a hydraulic tank on the opposite side; and the arm return oil merging Flow of pressure oil provided near the branch position of the pipe from the branch pipe for the arm and discharged from the hydraulic cylinder for the arm 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 of; and the outflow flow rate control valve for the boom, the outflow flow rate control valve for the arm, and the outflow flow rate control valve for the bucket. At the same time, they are collectively arranged in the one control valve device .

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.
Also, all the outflow flow control valves of the boom outflow flow control valve, the arm outflow flow control valve, and the bucket outflow flow control valve are collectively arranged in one control valve device together with all the inflow flow control valves. Since it is made into one block, as described in (1) above, welding work after loading and landing for foreign customers can be minimized as much as possible, and the rod inlet side inflow flow rate control valve is omitted and made so. As a result, one block can be reduced in size, and a predetermined transport restriction can be easily cleared at the time of loading or truck loading for public road transportation from the manufacturer to the port, thereby improving transportability.

(3) In the above (1) or (2 ), and preferably, the branch pipe supplied to the rod extrusion side chamber of each hydraulic cylinder is provided with a check valve.

(4) In any one of the above (1) to (3), and preferably, at least one of the inflow flow rate control valve and the outflow flow rate control valve is a seat valve.

(5) In the above (4), more preferably, the seat valve, a seat valve, its axis, but a substantially horizontal direction, opening and closing operation of the acceleration is the seat valve according to rotation of the front work device It is arranged so that it is perpendicular to the direction of.

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.
(6) Moreover, in order to achieve the said objective, this invention is connected to a traveling body, the revolving body provided in the upper part of this traveling body so that turning is possible, and this revolving body so that it can be raised / lowered, a boom, an arm And a hydraulic drive device for a construction machine provided in a construction machine having a multi-joint type front working machine including a bucket, a first hydraulic pump and a second hydraulic pump driven by a prime mover, and these first hydraulic pumps And a plurality of hydraulic cylinders including a boom hydraulic cylinder, an arm hydraulic cylinder, and a bucket hydraulic cylinder that are supplied with pressure oil discharged from the second hydraulic pump and respectively drive the boom, the arm, and the bucket; A plurality of directional flow control valves that respectively control the flow of pressure oil supplied from the first hydraulic pump to the plurality of hydraulic cylinders, and one side of which is the second hydraulic pressure A common high-pressure pipe connected to the discharge side of the pump, the other side extending to the front work machine side, and a branch from the common high-pressure pipe, and the other side connected to the rod extrusion side chamber of the boom hydraulic cylinder The boom branch pipe and the boom branch pipe are provided in the vicinity of a branch position from the common high-pressure pipe, and the pressure oil supplied from the common high-pressure pipe to the rod extrusion side chamber of the boom hydraulic cylinder. An inflow flow control valve for the boom that controls the flow, and an arm that branches from the branch position of the branch pipe for the boom of the common high-pressure pipe from the downstream side and is connected to the rod extrusion side chamber of the hydraulic cylinder for the arm A branch pipe for the arm and a branch position of the branch pipe for the arm from the common high-pressure pipe. An inflow flow control valve for the arm that controls the flow of pressure oil supplied to the push-out side chamber, and a branch 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 pressure for the bucket A branch pipe for the bucket connected to the rod extrusion side chamber of the cylinder, and a branch pipe of the bucket for the hydraulic cylinder rod provided near the branch position from the common high-pressure pipe. An inflow flow rate control valve for bucket that controls the flow of pressure oil supplied to the extrusion side chamber, and all inflow flow rate control of the inflow flow rate control valve for boom, the inflow flow rate control valve for arm, and the inflow flow rate control valve for bucket The valves are collectively arranged in one control valve device, and the one control valve device is arranged in the upper part of the boom, and the inflow flow rate control valve is constituted by a seat valve, It is assumed that the seat valve is arranged so that the axis thereof is in a substantially horizontal direction, and the acceleration due to the turning operation of the front work machine is perpendicular to the direction of the opening and closing operation of the seat valve.
( 7 ) 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 revolving body coupled to the revolving body so as to be able to be raised and lowered. And a hydraulic drive device for a construction machine provided in a construction machine having a multi-joint type front working machine including a bucket, a first hydraulic pump and a second hydraulic pump driven by a prime mover, and these first hydraulic pumps And a plurality of hydraulic cylinders including a boom hydraulic cylinder, an arm hydraulic cylinder, and a bucket hydraulic cylinder that are supplied with pressure oil discharged from the second hydraulic pump and respectively drive the boom, the arm, and the bucket; A plurality of directional flow control valves that respectively control the flow of pressure oil supplied from the first hydraulic pump to the plurality of hydraulic cylinders, and one side is the second oil A common high-pressure pipe connected to the discharge side of the pump, the other side extending to the front work machine side, and a branch from this common high-pressure pipe, and the opposite side was connected to the rod extrusion side chamber of the boom hydraulic cylinder The boom branch pipe and the boom branch pipe are provided in the vicinity of a branch position from the common high-pressure pipe, and the pressure oil supplied from the common high-pressure pipe to the rod extrusion side chamber of the boom hydraulic cylinder. An inflow flow control valve for the boom that controls the flow, and an arm that branches from the branch position of the branch pipe for the boom of the common high-pressure pipe from the downstream side and is connected to the rod extrusion side chamber of the hydraulic cylinder for the arm A branch pipe for the arm and a branch position of the branch pipe for the arm from the common high-pressure pipe. An arm inflow flow rate control valve that controls the flow of pressure oil supplied to the lid extrusion side chamber and a 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 for the bucket A branch pipe for the bucket connected to the rod extrusion side chamber of the hydraulic cylinder, and a branch position of the branch pipe for the bucket from the common high-pressure pipe are provided near the branch position of the bucket hydraulic cylinder. An inflow flow rate control valve for bucket that controls the flow of pressure oil supplied to the rod extrusion side chamber, and the plurality of inflow rate control valves are installed in the front work machine and configured by seat valves, The seat valve is arranged such that its axis is in a substantially horizontal direction, and the acceleration due to the turning operation of the front work machine is perpendicular to the direction of the opening / closing operation of the seat valve. And things.
Also in the present invention, as described in the above (1), the rod extrusion side is additionally provided for supplying a large flow rate in consideration of the volume difference between the rod extrusion side chamber and the rod drawing side chamber of each hydraulic cylinder. By using only the inflow flow control valve and omitting the rod inlet side inflow flow control valve, the pressure loss due to the flow control valve can be reduced by that amount, and the piping for installing the flow control valve can also be omitted. This can further reduce the overall pressure loss. 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. .
Further, in the present invention, a plurality of inflow flow rate control valves are installed in the front work machine and configured by a seat valve, and the seat valve has a substantially horizontal axis, and the front work machine is rotated. By arranging so that the acceleration due to is in a direction perpendicular to the direction of the opening / closing operation of the seat valve, even if the front work machine performs a rotating operation, the operating direction is a direction orthogonal to the axis, so the rotating operation is the seat It is possible to prevent the valve opening / closing operation itself from being affected and to ensure smooth and reliable valve operation.
( 8 ) In the above ( 7 ), preferably, all the inflow flow rate control valves of the boom inflow flow rate control valve, the arm inflow flow rate control valve, and the bucket inflow flow rate control valve are integrated into one control valve device. Place it centrally.
As a result, as described in (1) above, the welding work after loading and landing for foreign customers can be reduced as much as possible, and the rod inlet side inflow flow rate control valve can be omitted so that 1 The block can be reduced in size, and a predetermined transportation restriction can be easily cleared at the time of loading or truck loading for public road transportation from the manufacturer to the port, thereby improving transportability.
( 9 ) In the above ( 7 ), and preferably, the boom return oil merging branching 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 set of the three sets, and the plurality of outflow flow rate control valves are installed in the front work machine and configured by a seat valve, and the axis of the seat valve is substantially horizontal. The acceleration by the rotation operation of the front work machine is arranged in a direction perpendicular to the direction of the opening / closing operation of the seat valve.
As a result, as described in (6) above, even if the front work machine performs a rotation operation, the operation direction is a direction orthogonal to the axis, so that the rotation operation affects the opening / closing operation of the seat valve itself. Can be prevented, and smooth and reliable valve operation can be secured.
( 10 ) In the above ( 9 ), preferably, all of the inflow flow rate control valves for the boom, the inflow flow rate control valve for the arm, the inflow flow rate control valve for the bucket, the outflow flow rate control valve for the boom, the arm All the outflow flow rate control valves for the outflow flow rate control valve for the bucket and the outflow flow rate control valve for the bucket are centrally arranged in one control valve device.
As a result, as described in (1) above, the welding work after loading and landing for foreign customers can be reduced as much as possible, and the rod inlet side inflow flow rate control valve can be omitted so that 1 The block can be reduced in size, and a predetermined transportation restriction can be easily cleared at the time of loading or truck loading for public road transportation from the manufacturer to the port, thereby improving transportability.
( 11 ) In the above ( 8 ) or ( 10 ), and preferably, the one control valve device is provided on an upper portion of the boom.
(12) In any one of the above ( 7 ) to ( 11 ), more preferably, the branch pipe supplied to the rod extrusion side chamber of each hydraulic cylinder is provided with a check valve.

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.
In addition, according to the present invention, welding work after loading and landing for foreign customers can be reduced as much as possible, and the inflow flow rate control valve on the rod retracting side can be omitted to make one block smaller. In addition, it is possible to easily clear a predetermined transportation restriction at the time of loading or when loading a truck for public road transportation from the manufacturer to the port, and the transportability can be improved.
Furthermore, according to the present invention, even if the front work machine performs a rotation operation, the operation direction is a direction orthogonal to the axis, so that the rotation operation can be prevented from affecting the opening / closing operation itself of the seat valve, Smooth and reliable valve operation can be secured.

  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 through 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. Thus, when the boom lowering, arm dumping, and bucket dumping operations are performed, pressure is applied to the rod retracting side chambers 5aB, 5bB, 6B, 7B of the hydraulic cylinders 5a, 5b, 6, 7 through the control valves 10a, 10b, 10e, 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 the case where 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. The same parts as 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, while the bucket is closed and the bucket is dumped, the boom is lowered and the arm is pulled almost simultaneously.

  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 first reference example 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 this reference example . 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 and 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 reference example is an embodiment that embodies the above technical idea. 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 the 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 reference example , at least the number of flow control valves and the piping associated therewith can be reduced / omitted as compared with the case where an inflow flow control valve is also provided in the rod drawing side chamber. and it is possible to obtain the effectiveness of a layout simplification.

A second reference example 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 this reference example . The same parts as those in the first and second embodiments are denoted by the same reference numerals, and description thereof will be omitted as appropriate.

Contrary to the first reference example , in the case where only the pressure oil discharge from the rod extruding side chambers 5aA, 5bA, 6A, 7A needs to be considered, the inflow flow rate control valve in the first and second embodiments is used. 201, 202, 203, etc. Further, hydraulic pumps 3 a, 3 b, prime mover 4 b, pipes 102, 100, 104, pipes 150 </ b> A, 150 </ b> B, 150 </ b> C are provided with inflow flow control valves 201, 202, 203. It is sufficient to omit the bypass flow rate control valve 204, the relief valve 205 and the like and provide only the outflow flow rate control valves 211, 212, and 213.

This reference example is an embodiment that embodies the technical idea as described above. 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 boom hydraulic cylinder rod extrusion side chambers 5aA and 5bA (not shown) in the loader type hydraulic excavator. For example, in the case of the loader type embodiment described above, the arm outflow flow rate control valve 212 may be provided instead of the boom outflow flow rate control valve 211.

Also in this reference example , at least 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. and it is possible to obtain the effectiveness of a layout simplification.

Note that each of the flow control valves 201, 202, and 203 described in the first and second embodiments can be configured by a seat valve with relatively 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 , each flow control valve is disposed such 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 first and second embodiments described above are embodiments in which the present invention is applied to a hydraulic excavator, the present invention is widely applied to construction machines including other swiveling bodies, traveling bodies, and front working machines. 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. 1 is a hydraulic circuit diagram showing a configuration of a hydraulic drive device according to a first reference example of the present invention. FIG. 5 is a hydraulic circuit diagram showing a configuration of a hydraulic drive device according to a second reference example of the present 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 extruding side chambers 5aB, 5bB Rod retracting side chamber 6 Arm hydraulic cylinder 6A Rod extruding side chamber 6B Rod retracting side chamber 7 Bucket hydraulic cylinder 7A Rod extruding side chamber 7B Rod retracting 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 (12)

A traveling body, a revolving body constituting a vehicle body provided on the upper portion of the traveling body so as to be able to swivel, and an articulated front working machine connected to the revolving body so as to be able to move up and down and comprising a boom, an arm, and a bucket; In a hydraulic drive device for a construction machine provided in a construction machine having
A first hydraulic pump and a second hydraulic pump driven by a prime mover;
A third hydraulic pump driven by the prime mover;
The hydraulic oil discharged from the first hydraulic pump , the second hydraulic pump, and the third hydraulic pump is supplied, and the boom hydraulic cylinder, the arm hydraulic cylinder, and the bucket drive the boom, the arm, and the bucket, respectively. A plurality of hydraulic cylinders including hydraulic cylinders;
A plurality of first- direction flow rates that control the flow of pressure oil supplied from the first hydraulic pump to the plurality of hydraulic cylinders, respectively, and return the flow rates of pressure oil discharged from the plurality of hydraulic cylinders to the tanks, respectively. A control valve;
A plurality of second-direction flow rates for controlling the flow of pressure oil supplied from the second hydraulic pump to the plurality of hydraulic cylinders, respectively, and for returning the outflow flow rates of the pressure oil discharged from the plurality of hydraulic cylinders to the tanks, respectively. A control valve;
A common high-pressure pipe with one side connected to the discharge side of the third hydraulic pump and the other side extended to the front work machine side;
A branch pipe for the boom branched from the common high-pressure pipe on the front work machine side, and the opposite side connected to the rod extrusion side chamber of the boom hydraulic cylinder;
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 from the branch position of the branch pipe for the boom of the common high-pressure pipe on the front work machine side, 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 pipe for a bucket that branches from the downstream side of the branch position of the branch pipe for the boom of the common high-pressure pipe on the front work machine side, 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 flow control valve,
During the boom raising operation of extending the boom hydraulic cylinder, the pressure oil from the first hydraulic pump and the pressure oil from the second hydraulic pump are respectively supplied to the rod extrusion side chamber of the boom hydraulic cylinder. And a boom that shortens the boom hydraulic cylinder by supplying pressure oil from the third hydraulic pump via the boom inflow flow control valve and supplying the corresponding hydraulic pressure via the second direction flow control valve. During the lowering operation, only the pressure oil from the first hydraulic pump and the pressure oil from the second hydraulic pump are supplied to the rod retracting side chamber of the boom hydraulic cylinder, respectively, of the plurality of first and second directional flow control valves. Supply through the corresponding ones,
During the operation of extending the arm hydraulic cylinder, the pressure oil from the first hydraulic pump and the pressure oil from the second hydraulic pump are respectively supplied to the rod extrusion side chamber of the arm hydraulic cylinder. While supplying through the corresponding one of the two-way flow control valves, and supplying the pressure oil from the third hydraulic pump through the arm inflow flow control valve, the operation of shortening the arm hydraulic cylinder In the rod drawing side chamber of the arm hydraulic cylinder, only the pressure oil from the first hydraulic pump and the pressure oil from the second hydraulic pump correspond to the first and second directional flow control valves, respectively. Supply through
During the operation of extending the bucket hydraulic cylinder, the pressure oil from the first hydraulic pump and the pressure oil from the second hydraulic pump are respectively supplied to the rod extrusion side chamber of the bucket hydraulic cylinder. While supplying through the corresponding one of the two-way flow control valves, and supplying the pressure oil from the third hydraulic pump through the bucket inflow flow control valve to reduce the bucket hydraulic cylinder , Only the pressure oil from the first hydraulic pump and the pressure oil from the second hydraulic pump correspond to the plurality of first and second directional flow control valves respectively in the rod drawing side chamber of the bucket hydraulic cylinder. Configured to supply via
The plurality of first direction flow control valves and the plurality of second direction flow control valves are arranged on the vehicle body side, and all of the boom inflow flow control valve, the arm inflow flow control valve, and the bucket inflow flow control valve An inflow flow rate control valve is centrally arranged in one control valve device, and the one control valve device is arranged in the upper part of the boom. The hydraulic drive device for a construction machine according to claim 1,
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 And at least one of the three sets of bucket outflow flow rate control valves for controlling the flow of pressure oil discharged from the bucket hydraulic cylinder to the hydraulic tank and provided near the branch position from the branch pipe Prepared,
All the outflow flow control valves of the boom outflow flow control valve, the arm outflow flow control valve, and the bucket outflow flow control valve are collectively arranged in the one control valve device together with all the inflow flow control valves. A hydraulic drive device for construction machinery. The hydraulic drive device for a construction machine according to claim 1 or 2,
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 3,
Wherein at least one of the inlet flow control valve and the outlet flow control valve, a hydraulic drive system for a construction machine, characterized in that configured in the seat valve. The hydraulic drive device for a construction machine according to claim 4,
The construction is characterized in that the seat valve is arranged so that its axis is in a substantially horizontal direction, and the acceleration due to the turning operation of the front work machine is in a direction perpendicular to the direction of the opening / closing operation of the seat valve. Hydraulic drive device for the machine. A construction machine having a traveling body, a revolving body provided on the upper part of the traveling body so as to be able to swivel, and an articulated front working machine which is connected to the revolving body so as to be able to move up and down and which includes a boom, an arm, and a bucket. In the hydraulic drive device for construction machinery provided in
A first hydraulic pump and a second hydraulic pump driven by a prime mover;
The hydraulic oil discharged from the first hydraulic pump and the second hydraulic pump is supplied, and includes a boom hydraulic cylinder, an arm hydraulic cylinder, and a bucket hydraulic cylinder that respectively drive the boom, the arm, and the bucket. Hydraulic cylinders,
A plurality of directional flow control valves that respectively control the flow of pressure oil supplied from the first hydraulic pump to the plurality of hydraulic cylinders;
A common high-pressure pipe with one side connected to the discharge side of the second hydraulic pump and the other side extended 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 flow control valve,
All the inflow flow rate control valves of the boom inflow rate control valve, the arm inflow rate control valve, and the bucket inflow rate control valve are collectively disposed in one control valve device, and the one control valve device is provided. Placed at the top of the boom,
The inflow flow rate control valve is constituted by a seat valve,
The construction is characterized in that the seat valve is arranged so that its axis is in a substantially horizontal direction, and the acceleration due to the turning operation of the front work machine is in a direction perpendicular to the direction of the opening / closing operation of the seat valve. Hydraulic drive device for the machine. A construction machine having a traveling body, a revolving body provided on the upper part of the traveling body so as to be able to swivel, and an articulated front working machine which is connected to the revolving body so as to be able to move up and down and which includes a boom, an arm, and a bucket. In the hydraulic drive device for construction machinery provided in
A first hydraulic pump and a second hydraulic pump driven by a prime mover;
The hydraulic oil discharged from the first hydraulic pump and the second hydraulic pump is supplied, and includes a boom hydraulic cylinder, an arm hydraulic cylinder, and a bucket hydraulic cylinder that respectively drive the boom, the arm, and the bucket. Hydraulic cylinders,
A plurality of directional flow control valves that respectively control the flow of pressure oil supplied from the first hydraulic pump to the plurality of hydraulic cylinders;
A common high-pressure pipe with one side connected to the discharge side of the second hydraulic pump and the other side extended 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 flow control valve,
The plurality of inflow flow rate control valves are installed in the front work machine and configured by seat valves,
Construction in which the seat valve is arranged so that its axis is in a substantially horizontal direction, and the acceleration due to the turning operation of the front work machine is in a direction perpendicular to the direction of the opening and closing operation of the seat valve. Hydraulic drive device for the machine. The hydraulic drive device for a construction machine according to claim 7 ,
Hydraulic pressure for construction machinery, wherein all the inflow flow rate control valves of the inflow flow rate control valve for the boom, the inflow flow rate control valve for the arm, and the inflow flow rate control valve for the bucket are collectively disposed in one control valve device. Drive device. The hydraulic drive device for a construction machine according to claim 7 ,
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 And at least one of the three sets of bucket outflow flow rate control valves for controlling the flow of pressure oil discharged from the bucket hydraulic cylinder to the hydraulic tank and provided near the branch position from the branch pipe Prepared,
The plurality of outflow flow rate control valves are installed in the front work machine and configured with seat valves,
Construction in which the seat valve is arranged so that its axis is in a substantially horizontal direction, and the acceleration due to the turning operation of the front work machine is in a direction perpendicular to the direction of the opening and closing operation of the seat valve. Hydraulic drive device for the machine. The hydraulic drive device for a construction machine according to claim 9 ,
All the inflow flow rate control valves of the boom inflow rate control valve, the arm inflow rate control valve, the bucket inflow rate control valve, the boom outflow rate control valve, the arm outflow rate control valve, and the bucket outflow rate control valve A hydraulic drive device for a construction machine, wherein all the outflow flow rate control valves are centrally arranged in a single control valve device. The hydraulic drive device for a construction machine according to claim 8 or 10 ,
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 7 to 11 ,
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.

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