JP3853314B2 - Hydraulic work machine - Google Patents

Description

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

  As an example of a hydraulic work machine, for example, an ultra-large hydraulic excavator of 70t class is an ultra-large machine, and therefore it is necessary to supply a large amount of hydraulic oil in order to drive particularly the bottom side of a plurality of hydraulic cylinders provided. . Such a conventional hydraulic working machine that takes into account the supply of a larger flow rate than usual includes one hydraulic pump driven by a prime mover and another hydraulic pump, and discharge from these two hydraulic pumps. Connected between hydraulic cylinder for boom driven by oil, one control valve connected between one hydraulic pump and hydraulic cylinder for boom, and between other hydraulic pump and hydraulic cylinder for boom Other control valves, and one control valve and another control valve, and a hydraulic pipe line that respectively connects the bottom side and the rod side of the boom hydraulic cylinder are disclosed (for example, Patent Document 1). .

  In this prior art, the pressure oil discharged from one hydraulic pump via the one control valve and the pressure oil discharged from another hydraulic pump and the other control valve are merged to form the bottom of the boom hydraulic cylinder. In addition to supplying to the side or the rod side, the return oil is divided and discharged to the tank via one control valve and another control valve.

JP 56-115428 (Fig. 1)

  In the above prior art, pressure oil from other hydraulic pumps and other control valves is combined with a normal configuration in which pressure oil is supplied from one hydraulic pump to the boom hydraulic cylinder via one control valve. Thus, it is possible to supply pressure oil having a flow rate about twice as high.

  Here, in order to supply pressure oil with a super-high pressure and a super-large flow rate than usual, it is necessary to configure the main pipeline with a super-large-diameter hose or steel pipe. The existing hose has a maximum diameter of about 2 inches, and a large number (for example, two or three) must be arranged. 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, the entire hydraulic circuit including long pipes and control valves (flow control switching valves) composed of hoses, steel pipes, etc. for ultra-large machines causes very large pressure loss, increases energy loss, and increases hydraulic pressure. There is a problem that the operating speed of the actuator is lowered and work efficiency is deteriorated. Further, in a super-large machine, it is not easy to arrange one main pipe line constituted by arranging a large number of hoses and the like in a hydraulic cylinder for a boom as described above. There is also a problem that worsens the visibility of the side and rear of the working machine.

  An object of the present invention is to provide a hydraulic working machine that can reduce the total pressure loss by reducing the total number of pipes such as the number of hoses and steel pipes even when applied to a super large machine.

In order to achieve the above object, according to the present invention, there is provided a front device comprising a vehicle body that is a work implement main body, and a plurality of front members that are pivotably connected to the work implement main body in the vertical direction. In hydraulic work machines,
At the vehicle body side, at least one hydraulic pump, a plurality of flow rate control switching valves for controlling the pressure oil discharged from the hydraulic pump, at least one other hydraulic pump, and the other hydraulic pump are discharged. And a discharge pipe through which the pressurized oil is guided ,
The front device side includes a plurality of hydraulic cylinders that respectively drive the plurality of front members, and a plurality of hydraulic cylinders that respectively connect either the bottom side or the rod side of the hydraulic cylinder corresponding to the flow rate control switching valve. A first connection line; a second connection line connected on one side to the discharge line of the other pump; a plurality of branch points provided on the other side of the second connection line; A plurality of first pipes each connected to one of the points and connected to at least one of the plurality of first connection pipes connected to at least the bottom side of the hydraulic cylinder; Each of the plurality of first members is provided on each of the plurality of first pipes so as to be located on the bottom side of the corresponding hydraulic cylinder with respect to the branch point. A plurality of first flow rate control means for controlling the flow of pressure oil from the pump toward the bottom side of the corresponding hydraulic cylinder ;
Hydraulic work characterized in that, on the front device side, the pressure oil from the other hydraulic pump is guided to the bottom side of a plurality of hydraulic cylinders via a second connection pipe which is a common supply line. A machine is provided.

In other words, for example, when considering the extension operation of each hydraulic cylinder, the pressure oil discharged from at least one hydraulic pump (vehicle body side) is provided on the front side via a plurality of flow rate control switching valves provided on the vehicle body side. In addition, the first connection pipe line is supplied to the one connected to the bottom side of each hydraulic cylinder. At the same time, the pressure oil discharged from at least one other hydraulic pump is also discharged from the discharge line provided on the vehicle body side, the second connection line as a common supply line provided at the front side , the branch point, and The first connecting pipe is installed in one of the front members through the first pipe connected to at least one of the first connecting pipes connected to the bottom side of the hydraulic cylinder , and the flow rate is set in one of the front members. It is adjusted by the first flow rate control means provided in the first pipeline so as to be located on the bottom side of the hydraulic cylinder corresponding to the branch point, and is connected to the bottom side without passing through the flow rate control switching valve. Supplied to each first connecting pipe. As a result, for example, a very large flow rate of pressure oil can be guided to the bottom side of a corresponding hydraulic cylinder in a super-large machine, and the hydraulic cylinder can be driven in the extending direction to operate the front members.

Here, for example, simply, at least one hydraulic pump, a plurality of flow control switching valves are added to the vehicle body side, and a plurality of first connection pipes are added to the front device side, and the downstream side of the added first connection pipe is originally provided. Even if it is connected to a certain first connection pipe line, it is possible to cope with the expansion and contraction operations of each hydraulic cylinder as described above, for example, in an ultra-large machine with an ultra-high flow rate. However, in this case, the first flow rate control switching is performed as a first connection pipe that is a high-pressure line on the bottom side of each hydraulic cylinder provided in the order of the boom cylinder, the arm cylinder, and the bucket cylinder from the work machine main body side on the front device side . For example, two valves are provided from the valve group and the second flow rate control switching valve group. Therefore, the number of high-pressure line pipes (supply pipe lines) from the vehicle body side on the front device side to the bottom side of each hydraulic cylinder, that is, the boom cylinder, arm cylinder, and bucket cylinder, is closer to the front device side than the boom cylinder. Then, a total of six first connection pipe lines to the bottom side of the boom cylinder, two first connection pipe lines to the bottom side of the arm cylinder, and two first connection pipe lines to the bottom side of the bucket cylinder. The sum of the first connecting pipe line to the bottom side of the arm cylinder and the two first connecting pipe lines to the bottom side of the bucket cylinder, in front of the arm cylinder beyond the boom cylinder on the front device side. 4 is present in the front of the bucket cylinder beyond the arm cylinder of the front device side, a first connecting line 2 to the bottom side of the bucket cylinder

On the other hand, in the present invention, the hydraulic pump, the flow control switching valve, the other hydraulic pump, and the discharge pipe are provided on the vehicle body side ( work machine body ) , and the first connection pipe, the common supply pipe the second connecting line is a road branch point, first conduit, the first flow control means, and the hydraulic cylinder is installed on the front device. That is, on the front device side, the first flow rate control means is installed in one of the front members and is provided in the first pipeline so as to be located on the bottom side of the corresponding hydraulic cylinder with respect to the branch point. 1 The flow rate control means and the branch point are arranged so as to be close to the corresponding hydraulic cylinders, and the pressure oil from other hydraulic pumps is supplied to the bottom side of the plurality of hydraulic cylinders via the second connection pipe which is a common supply line. Configured to guide. In this way, on the front device side, it is only necessary to provide a second connection pipe that is a common supply pipe to each branch point close to the bottom side of each hydraulic cylinder. Number) can be reduced and the extension can be shortened, and the pressure loss of the entire high-pressure line can be reduced.
For example, on the front device side, the first connection line from the position near the boom cylinder of the second connection line that is a common supply line to the bottom side of the boom cylinder is branched, and the second connection line is further advanced. The first pipeline from the position close to the arm cylinder to the bottom side of the arm cylinder is branched, and further forward, the first pipeline from the position near the bucket cylinder of the second connection pipeline to the bottom side of the bucket cylinder Branching, the number of high-pressure lines to the bottom of each hydraulic cylinder, which is a particular problem when considering pressure loss, is reduced in the majority of the front device side compared to the case where the conventional structure is applied. . Specifically, the number of high-pressure lines is one on the front device side before the branch point of the first pipe line to the boom cylinder, one first connection pipe line to the boom cylinder bottom side, and the arm arm cylinder bottom side. There are a total of four lines, one first connecting line to the first side, one first connecting line to the bucket cylinder bottom side, and one second connecting line, and the arm extends beyond the boom cylinder on the front device side. Before the branch point of the first pipe line to the cylinder, one first connection pipe line to the arm cylinder bottom side, one first connection pipe line to the bucket cylinder bottom side, and one second connection pipe line Thus, the number of high-pressure line pipes to the bottom side of each hydraulic cylinder can be reduced so far. Therefore, the number of hoses (or the number of steel pipes) in the entire high-pressure line can be reduced correspondingly, and the extension can be shortened, so that the pressure loss in the entire high-pressure line can be reduced. In addition, in the front device side, before the branch point of the first pipe line to the bucket cylinder beyond the arm cylinder, a total of two first connection pipe lines and two second connection pipe lines to the bucket cylinder bottom side Thus, the number is the same as the conventional one, but since the number is not increased as compared with the conventional one, the pressure loss does not increase.

Preferably, in the hydraulic working machine, a hydraulic tank and a tank conduit for guiding pressure oil to the hydraulic tank are provided on the vehicle body side, and one side is provided on the tank conduit on the front device side. a third connection conduit connected, before SL and a plurality of branch points provided on the other side of the third connecting pipeline, whereas with side are respectively connected to one of the branch point, the other side of the plurality A plurality of second pipes respectively connected to at least one of the three connection pipes connected to the bottom side of the hydraulic cylinder, and the branch point respectively installed on one of the plurality of front members A plurality of second pipes that are provided on the bottom side of the corresponding hydraulic cylinders to control the flow of pressure oil from the corresponding hydraulic cylinders toward the third connection pipes. Second flow rate And control means arranged, in the above front device side, characterized in that the pressure oil from the bottom side of said plurality of hydraulic cylinders via a common third connecting tube is discharge line configured to direct to the hydraulic tank A hydraulic work machine is provided.
In order to achieve the above object, according to the present invention, there is provided a front apparatus comprising a vehicle body that is a work implement main body, and a plurality of front members that are pivotably connected to the work implement main body in the vertical direction. In the hydraulic working machine, on the vehicle body side, at least one hydraulic pump, a plurality of flow control switching valves for controlling the pressure oil discharged from the hydraulic pump, at least one other hydraulic pump, a discharge line which pressure oil discharged from the other hydraulic pump is guided, and the hydraulic tank, hydraulic oil and provided a tank line leading to the hydraulic tank, the front device side, said plurality of front members A plurality of hydraulic cylinders respectively driving the flow control switching valve, and a plurality of first connection pipes respectively connecting either the bottom side or the rod side of the hydraulic cylinder corresponding to the flow rate control switching valve; A second connection line connected to the discharge line on the other side, a plurality of branch points provided on the other side of the second connection line, and one side connected to one of the branch points, A plurality of first pipes connected to at least one of the plurality of first connection pipes connected to at least the bottom side of the hydraulic cylinder, and one of the plurality of front members, respectively. And provided in each of the plurality of first pipes so as to be located on the bottom side of the corresponding hydraulic cylinder side with respect to the branch point, and the flow of the pressure oil from the other hydraulic pump toward the hydraulic cylinder A plurality of first flow rate control means for allowing pressure oil to flow from the hydraulic cylinder to the other hydraulic pump and allowing one side to the tank pipe line while allowing the variable throttle to control to a desired throttle amount. A third connected connection line, a plurality of branch points provided on the other side of the third connection line, one side connected to one of the branch points, and the other side connected to the plurality of third points A plurality of second pipes connected to at least one of the connecting pipes connected to the bottom side of the hydraulic cylinder, and one of the plurality of front members, respectively, and from the branch point Are respectively provided in the plurality of second pipes so as to be positioned on the bottom side of the corresponding hydraulic cylinders, and control the flow of pressure oil from the hydraulic cylinders to the third connection pipes to a desired throttle amount. with allowable via the variable stop, and a plurality of second flow control means for interrupting the flow of pressure oil flowing from the third connecting pipeline to the hydraulic cylinder is provided, at the front device side, from the other hydraulic pump The pressure oil is guided to the bottom side of the plurality of hydraulic cylinders via the second connection pipe that is a common supply pipe, and the pressure oil from the bottom side of the plurality of hydraulic cylinders is a third connection that is a common discharge pipe. A hydraulic work machine is provided which is configured to be guided to the hydraulic tank through a pipe .

  According to the present invention, the number of supply-side pipelines in most of the front apparatus is reduced as compared with the case where the conventional structure is applied. Therefore, the total number of hoses can be reduced and the hose extension can be shortened accordingly. Therefore, since the overall pressure loss can be reduced, energy loss can be reduced, the operating speed of the hydraulic cylinder can be increased, and work efficiency can be improved.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings. This embodiment is an embodiment in a case where the present invention is applied to, for example, a 70 t class super large hydraulic excavator.

  First, a hydraulic circuit representing a configuration of a hydraulic drive device provided in the hydraulic work machine according to the present embodiment is shown in FIG. 1 together with its control device.

  1 includes a first hydraulic pump 1a and a second hydraulic pump 1b driven by a prime mover 4a, a third hydraulic pump 3a and a fourth hydraulic pump 3b driven by a prime mover 4b, Boom hydraulic cylinders 5a and 5b and arm hydraulic cylinders 6 driven by oil discharged from the first and second hydraulic pumps 1a and 1b, and buckets driven by oil discharged from the first hydraulic pump 1a A hydraulic cylinder 7 and a turning hydraulic motor 8 driven by oil discharged from the second hydraulic pump 1b are provided.

The first hydraulic pump 1a includes boom hydraulic cylinders 5a and 5b, an arm hydraulic cylinder 6, and a first boom control valve 10c, a first arm control valve 10b, and a first bucket control valve 10a, respectively. Connected to the bucket hydraulic cylinder 7, the second hydraulic pump 1b includes boom hydraulic cylinders 5a, 5b, a second boom control valve 10d, a second arm control valve 10e, and a turning control valve 10f, respectively. The arm hydraulic cylinder 6 and the turning hydraulic motor 8 are connected. These control valves 10 a to 10 f constitute a control valve group 10.
The bottom sides of the boom hydraulic cylinders 5a and 5b and the first and second boom control valves 10c and 10d are connected by a main pipe 105 as a first connection pipe, and the boom hydraulic cylinders 5a and 5b are connected to each other. The rod side and the first and second boom control valves 10c, 10d are connected by a main pipeline 115 as a first connection pipeline. Further, the bottom side of the arm hydraulic cylinder 6 and the first and second arm control valves 10b and 10e are connected by a main pipe 116 as a first connection pipe, and the rod side of the arm hydraulic cylinder 6 is connected. The first and second arm control valves 10b and 10e are connected by a main line 106 as a first connection line. Further, the bottom side of the bucket hydraulic cylinder 7 and the bucket control valve 10a are connected by a main pipe 107 as a first connection pipe, and the rod side of the bucket hydraulic cylinder 7 and the first bucket control valve are connected. 10a is connected by a main pipe line 117 as a first connection pipe line. Further, the turning hydraulic motor 8 and the turning control valve 10f are connected by main pipes 108 and 118 as first connection pipes.

  On the other hand, the third and fourth hydraulic pumps 3a and 3b are provided in the discharge pipe 102 to which the pressure oil discharged from the hydraulic pumps 3a and 3b is guided and the front device 14, and one side (the left side in the figure) is the discharge pipe. A supply pipe 100 as a second connection pipe connected to the pipe 102 and a branch pipe as a first pipe connected to the front device 14 so as to branch from the other side of the supply pipe 100. The main lines 105, 115, 116, 106, 107, and 117 are connected to the main lines 105A, B, C, D, E, and F, respectively. Among these branch pipes 150A to 150F, the flow of pressure oil from the third and fourth hydraulic pumps 3a, 3b to the bottom side of the hydraulic cylinders 5a, 5b, 6, 7 is supplied to the branch pipes 150A, C, E. First flow rate control means for allowing a variable throttle to control a desired throttle amount and blocking the reverse flow, for example, flow rate control valves 15, 17, and 19 including electromagnetic proportional valves with a pressure compensation function are provided. In the branch pipes 150B, D, and F, the flow of pressure oil from the third and fourth hydraulic pumps 3a and 3b toward the rods of the hydraulic cylinders 5a, 5b, 6, and 7 is controlled to a desired throttle amount. There are provided first flow rate control means for permitting the flow through the variable throttle and blocking the reverse flow, for example, flow rate control valves 65, 67, 69 composed of, for example, an electromagnetic proportional valve with a pressure compensation function.

  At this time, the branch positions of the branch pipelines 150A to 150F from the supply pipeline 100 are arranged in the vicinity of the corresponding hydraulic cylinders (see also FIG. 2 described later). That is, the branch pipes 150A and B to the boom cylinders 5a and 5b branch from the position near the boom cylinders 5a and 5b of the supply pipe 100, and proceed further to the arm cylinder from the position near the arm cylinder 6 of the supply pipe 100. The branch pipelines 150C and D to 6 are branched, and further forward, the branch pipelines 150E and F to the bucket cylinder 7 are branched from the position near the bucket cylinder 7 of the supply pipeline 100.

  The hydraulic tank 2 includes a tank line 103 that guides return oil to the hydraulic tank 2, a low pressure third connection line that is provided in the front device 14 and one side (the left side in the drawing) is connected to the tank line 103. , And branch pipes 151A, B, C, D, E, and F as second pipes that are connected to the front device 14 so as to branch from the other side of the discharge pipe 101, respectively. Are connected to the main pipelines 105, 115, 116, 106, 107 and 117, respectively. Of these branch pipes 151A to 151F, the branch pipes 151A, 151C, and 151E control the flow of pressure oil from the bottom side of the hydraulic cylinders 5a, 5b, 6, and 7 to the hydraulic tank 2 to a desired throttle amount. There are provided three second flow rate control means for allowing the variable throttle and blocking the reverse flow, for example, flow rate control valves 16, 18, and 20 consisting of electromagnetic proportional valves, and branch lines 151B, D, and F are provided. Includes three variable pressure valves that allow the flow of pressure oil from the rod side of the hydraulic cylinders 5a, 5b, 6, 7 to the hydraulic tank 2 through a variable throttle that controls the throttle amount to a desired value, and block the reverse flow. Two flow rate control means, for example, flow rate control valves 66, 68, 70 comprising electromagnetic proportional valves are provided.

  At this time, the branch positions of the branch pipes 151A to 151F from the discharge pipe 101 are arranged in the vicinity of the corresponding hydraulic cylinders (see also FIG. 2 described later). That is, the branch lines 151E and F from the bucket cylinder 7 merge at a position in the vicinity of the bucket cylinder 7 of the discharge pipe 101, and further return to the vehicle body 13 side so that the branch lines 151C and D from the arm cylinder 6 are the discharge pipes. 101, the branch pipes 151A, B from the boom cylinders 5a, 5b join at a position near the boom cylinders 5a, 5b in the discharge pipe 101.

  The flow control valves 15 to 20 and 65 to 70 described above are flow control valves 15 and 16, flow control valves 17 and 18, flow control valves 19 and 20, flow control valves 65 and 66, which are disposed relatively close to each other. The flow rate control valves 67 and 68 and the flow rate control valves 69 and 70 constitute the flow rate control valve devices 51, 61, 71 (see FIG. 2 described later) and 52, 62, 72, respectively.

Further, a pipe 104 is branched into the discharge pipe 102, and a desired amount of the pressure oil discharged from the third and fourth hydraulic pumps 3 a and b is supplied to the pipe 104. In addition, a third flow rate control means for returning the rest to the hydraulic tank 2, for example, a bypass valve 21 comprising an electromagnetic proportional valve having a pressure compensation function is provided. A relief valve 22 that defines the maximum pressure of the supply line 100 that is a high-pressure line is provided between the discharge line 102 and the tank line 103.
The first to fourth hydraulic pumps 1a, 1b, 3a, 3b, the control valve group 10, the discharge pipe 102, the tank pipe 103, the pipe 104, the bypass valve 21, the relief valve 22 and the like are shown in FIG. As shown in FIG. 1, the hydraulic cylinders 5a, 5b, 6, and 7, the supply pipe 100, the discharge pipe 101, the branch pipes 150A to F and 151A to F are provided on the front side. The device 14 is provided. In addition, among the above configurations, the third and fourth pumps 3a and 3b constitute other hydraulic pumps provided in the vehicle body 13 separately from the first and second hydraulic pumps 1a and 1b.

  In the configuration shown in FIG. 1, the low-pressure line may be a single large hose (or steel pipe) instead of two hoses (or steel pipes).

  FIG. 2 is a side view showing the overall structure of a hydraulic excavator as an embodiment of the hydraulic work machine of the present invention, which is a drive target of the hydraulic drive device as described above. In FIG. 2, the hydraulic excavator includes a vehicle body 13 that is a working machine body and a plurality of front members that are rotatably connected to the vehicle body 13 in the vertical direction, that is, a boom 75, an arm 76, and a bucket 77. A device 14 is provided. The boom hydraulic cylinder 5, 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. Arm cloud and bucket cloud are performed. The turning hydraulic motor 8 shown in FIG. 1 is mounted inside the turntable 78 and turns the turntable 78. Although not shown in FIG. 1, traveling hydraulic motors that drive a traveling device 79 of a hydraulic excavator are connected to the first and second hydraulic pumps 1a and 1b via control valves, respectively.

  The main pipe lines 105, 115, 106, 116, 107, 117, the supply pipe line 100, the discharge pipe line 101, and the flow control valve devices 51, 61, 71, 52, 62, 72 are provided in the front device 14, respectively. (However, the main pipe line 105 and the flow rate control valve devices 51, 52, 62, 72 are not shown in order to prevent complications).

  Returning to FIG. 1, a calculator 131 is provided as a control device of the hydraulic drive device. The calculator 131 receives the operation signals output from the operation levers 32 and 33, and outputs command signals to the control valves 10 a to 10 f, the flow control valves 15 to 20 and 65 to 70, and the bypass valve 21. 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.

  A functional block diagram showing the detailed functions of the computing unit 131 is shown in FIG.

As shown in this figure, the arithmetic unit 131 inputs an operation signal from the operation levers 32 and 33, switches and selects it, and outputs it. The operation signal output through the multiplexer 34 is converted into a digital signal. An A / D converter 35 for conversion, a RAM 36 for temporarily storing these signals, a ROM 37 for storing a control program for executing processing procedures to be described later, and operation signals are stored in the ROM 37. A central processing unit that processes according to the control program, that is, the CPU 38, the control valves 10a to f, the flow rate control valves 15 to 20, 65 to 70, and the output port 39 that amplifies and outputs the output from the CPU 38 to the bypass valve 21. It has become.
In the ROM 37, in addition to a general control program for controlling the control valves 10a to 10f in accordance with the operation signals of the operation levers 32 and 33, a flow rate control valve 15 as shown in FIGS. Control programs for controlling ˜20, 65 to 70 and the bypass valve 21 are stored.
Next, the operation of the hydraulic excavator of the present embodiment provided with the hydraulic drive apparatus configured as described above will be described with reference to the flowcharts shown in FIGS.
In the hydraulic excavator as shown in FIG. 2, the boom 75, the arm 76, and the bucket 77 constituting the front device 14 are the boom raising, the arm cloud, and the bucket cloud corresponding to the extending operation of each hydraulic cylinder 5-7. Each operation is generally an operation in which the required flow rate is large and the load is also large. For this reason, in the computing unit 131, the operation signals for the front device 14 output from the operation levers 32 and 33 are the boom raising operation signal, the arm cloud operation signal, the bucket cloud operation signal, and others. , That is, an operation signal for instructing an extension operation of the front hydraulic cylinders 5 to 7 and other operation signals.
That is, first, when the operation levers 32 and 33 are operated, the operation signals are a boom raising operation signal (abbreviated as operation signal (1)) and an arm cloud operation signal (hereinafter abbreviated as operation operation (2)). ), Whether it is one of each operation signal of the bucket cloud operation signal (hereinafter abbreviated as operation signal (3)), or the boom lowering operation signal (abbreviated as operation signal (4)), arm dump It is determined whether or not the operation signal is one of operation signals (hereinafter abbreviated as operation operation (5)) and bucket dump operation signal (hereinafter abbreviated as operation signal (6)) (step S1).

  When the operation signal is one of the above operation signals (1) (2) (3) (4) (5) (6), it is the operation signal (1) (2) (3) (4) ( 5) Different processing is performed depending on which of (6).

  That is, when the operation signal is (1), the bypass valve 21 is closed, the flow control valves 15, 66 are opened, and the other flow control valves 16-20, 65, 67-70 are closed (step S2). As a result, in addition to the oil discharged from the first and second hydraulic pumps 1a and 1b, the oil discharged from the third and fourth hydraulic pumps 3a and 3b joins to the bottom side of the boom hydraulic cylinders 5a and 5b. The return oil from the rod side of the boom hydraulic cylinders 5a and 5b is discharged to the hydraulic tank 2 through the main pipeline 115 and the control valves 10c and 10d, and the branch pipeline 151B. Also, the oil is discharged to the hydraulic tank 2 through the discharge pipe 101. This makes it possible to increase the speed of the extension operation of the hydraulic cylinders 5a and 5b or to perform a high load operation.

  When the operation signal is (2) or (3), similarly, the bypass valve 21 is closed, the flow control valve 17, 68 or 19, 70 is opened, and the other flow control valves are closed (step S3). , S4). As a result, the discharge oil from the third and fourth hydraulic pumps 3a, 3b is also joined and supplied to the bottom side of the arm hydraulic cylinder 6 or the bucket hydraulic cylinder 7, and the arm hydraulic cylinder 6 or bucket The return oil from the rod side of the hydraulic cylinder 7 is discharged to the hydraulic tank 2 via the main pipe line 106 or 117 and the control valve 10b, 10e or 10a, and the branch pipe line 151D or 151F and the discharge pipe line 101. Are also discharged to the hydraulic tank 2. This makes it possible to increase the speed of the extension operation of the hydraulic cylinder 6 or 7 or to perform a high load operation.

  Further, when the operation signal is (4), the bypass valve 21 is closed, the corresponding flow control valves 16, 65 are opened, and the other flow control valves are closed (step S5). As a result, in addition to the oil discharged from the first and second hydraulic pumps 1a and 1b, the oil discharged from the third and fourth hydraulic pumps 3a and 3b joins the rod side of the boom hydraulic cylinders 5a and 5b. The return oil from the bottom side of the boom hydraulic cylinders 5a and 5b is discharged to the hydraulic tank 2 via the control valves 10c and 10d, and the discharge pipe 101 and the tank pipe Also through 103, the oil is discharged into the hydraulic tank 2. As a result, the speed of the contracting operation of the hydraulic cylinders 5a and 5b can be increased.

Further, when the operation signal is (5) or (6), similarly, the bypass valve 21 is closed, the flow control valves 18, 67 or 20, 69 are opened, and the other flow control valves are closed (step S6). , S7). As a result, the discharge oil from the third and fourth hydraulic pumps 3a and 3b is also supplied to the rod side of the arm hydraulic cylinder 6 or the bucket hydraulic cylinder 7, and is supplied to the arm hydraulic cylinder 6 or bucket. The return oil from the bottom side of the hydraulic cylinder 7 is discharged to the hydraulic tank 2 via the control valve 10b, 10e or 10a, and also to the hydraulic tank 2 via the discharge pipe 101 and the tank pipe 103. Discharged. As a result, the speed of the contraction operation of the hydraulic cylinder 6 or 7 can be increased.
Next, when there are two or more of the operation signals (1), (2), (3), (4), (5), and (6), it is determined whether or not these operation signals are two. (Step S8), if there are two, different processing is performed depending on which combination of the operation signals (1) (2) (3) (4) (5) (6).
That is, in the case of the operation signals (1) and (2), it is first determined whether or not the difference in the operation amount indicated by each operation signal (1) and (2) is greater than or equal to a certain value (step S9). In this case, the bypass valve 21 is closed and the flow rate control valves 15, 66 and 17, 68 are proportional so that their opening degrees are proportional to the operation amounts of the operation signals (1) and (2). Then, the other flow control valves are closed (step S10). As a result, the oil discharged from the third and fourth hydraulic pumps 3a and 3b on the bottom side of the boom hydraulic cylinders 5a and 5b and the arm hydraulic cylinder 6 corresponds to the ratio of the operation amount of the operation signals (1) and (2). And the return oil from the rod side of the boom hydraulic cylinders 5a and 5b and the arm hydraulic cylinder 6 is also in accordance with the ratio of the operation amount of the operation signals (1) and (2). The flow is divided and discharged. Therefore, the combined operation of raising the boom and the arm cloud adapted to the operation amount ratio indicated by the operation signals (1) and (2) can be performed using the discharge oil of the third and fourth hydraulic pumps 3a and 3b. it can.
When the difference between the operation amounts of the operation signals (1) and (2) is equal to or larger than a certain value and the operation signal (1) is larger than (2), the bypass valve 21 is closed and the flow control valves 15 and 66 are opened. The flow control valve is closed (step S11). As a result, the oil discharged from the third and fourth hydraulic pumps 3a and 3b is supplied to the bottom side of only the boom hydraulic cylinders 5a and 5b and is returned from the rod side of only the boom hydraulic cylinders 5a and 5b. The oil branches off and is discharged to the hydraulic tank 2. The reason for this is as follows.

In general, a hydraulic excavator has a pile work in which the bucket 77 is piled up by pulling the bucket 77 to the main body side after excavation. At this time, in order to pull the bucket 77 toward the main body side, the arm 76 is clouded while raising the boom 75. At this time, the load pressure of the boom raising is extremely large, while the load pressure of the arm cloud is smaller than that. Therefore, in order to avoid the situation where the hydraulic pump discharge oil is supplied only to the lightly loaded hydraulic cylinder for the arm and the boom cannot be raised, the maximum operating amount of the operating lever for the boom is set to the maximum operating amount of the operating lever for the arm. Use a very small amount. In such a combined operation, it is desired to supply as much pressure oil as possible to the boom hydraulic cylinders 5a and 5b and to pull the bucket 77 quickly. Therefore, when the difference between the operation amounts of the operation signals (1) and (2) is a certain value or more and the operation signal (1) is larger than (2), it is determined that this combined operation is performed, and as described above. The oil discharged from the third and fourth hydraulic pumps 3a, 3b is supplied to the bottom side of only the boom hydraulic cylinders 5a, 5b. As a result, the boom is quickly raised, and in the stacking operation, the bucket is drawn to the main body side in a short time, and the operation is rationalized.
When the operation signal is (1) (3) or (2) (3), the bypass valve 21 is closed and the flow control valves 15, 19, 66, 70 or 17, 19, 68, 70 are Is controlled proportionally so that the opening is proportional to the operation amount of the operation signal (1) (3) or (2) (3), and the other flow control valves are closed (step S12 or S13). As a result, the oil discharged from the third and fourth hydraulic pumps 3 is supplied to the bottom side of the boom hydraulic cylinder 5 and the bucket hydraulic cylinder 7 or the arm hydraulic cylinder 6 and the bucket hydraulic cylinder 7 as the operation signal (1). (3) or (2) Combined and supplied at a flow rate distributed according to the operation amount ratio of (3), the boom hydraulic cylinder 5 and the bucket hydraulic cylinder 7 or the arm hydraulic cylinder 6 and the bucket The return oil from the rod side of the hydraulic cylinder 7 is also branched and discharged at a flow rate that is distributed according to the operation amount ratio of the operation signal (1) (3) or (2) (3). Therefore, the boom raising and the bucket cloud or the combined operation of the arm cloud and the bucket cloud adapted to the operation amount ratio indicated by the operation signals (1), (3) or (2), (3) are performed by the third and fourth hydraulic pumps. The discharge oil of 3a and 3b can also be used.
Here, in particular, the combined operation of the operation signals (2) and (3) is when light excavation by arm cloud and bucket cloud is performed, and it is desirable to perform bucket cloud surely regardless of load fluctuations in this work. It is. According to the present embodiment, when the load pressure of the bucket hydraulic cylinder 7 is smaller than the load pressure of the arm hydraulic cylinder 6, the discharge oil of the third and fourth hydraulic pumps 3a and 3b is proportionally distributed to be used for the bucket. By being also supplied to the hydraulic cylinder 7, it is possible to speed up light excavation work, and even when the load pressure of the bucket hydraulic cylinder 7 is larger, the pressure oil of the third and fourth hydraulic pumps 3a and 3b is increased. Since the oil is reliably supplied to the hydraulic cylinder 7, it is possible to avoid a situation in which the hydraulic cylinder 7 does not move.
Next, when the operation signal is (1) (5) or (1) (6), the bypass valve 21 is closed and the flow control valves 15, 18, 66, 67 or 15, 20, 66, 69 are opened. The other flow control valves are closed (steps S14 and S15). As a result, the oil discharged from the third and fourth hydraulic pumps 3a and 3b is supplied to the bottom side of the boom hydraulic cylinders 5a and 5b, and returned oil from the rod side of the boom hydraulic cylinders 5a and 5b. Branches off and is discharged to the hydraulic tank 2. Then, the discharge oil of the third and fourth hydraulic pumps 3a, 3b is supplied to the rod side of the arm hydraulic cylinder 6 or the bucket hydraulic cylinder 7 and supplied, and the arm hydraulic cylinder 6 or the bucket hydraulic cylinder 7 is supplied. The return oil from the bottom side is discharged into the hydraulic tank 2 not only through the control valve 10b, 10e or 10a but also through the discharge pipe line 101 and the tank pipe line 103. Therefore, the combined operation of raising the boom and arm dumping or bucket dumping can be performed with high efficiency and high speed with little pressure loss.
Similarly, when the operation signal is (2) (4) or (2) (6), the bypass valve 21 is closed and the flow control valves 16, 17, 65, 68 or 17, 20, 68, 69 are turned on. The other flow control valves are opened and closed (steps S16 and S17). When the operation signal is (3) (4) or (3) (5), the bypass valve 21 is closed and the flow control valves 16, 19, 65, 70 or 18, 19, 67, 70 are opened. Are closed (steps S18, S19). As a result, the oil discharged from the third and fourth hydraulic pumps 3a and 3b is supplied to the bottom side or the rod side of the corresponding hydraulic cylinder, and the return oil from the rod side or the bottom side is supplied to the corresponding control valve 10. In addition, since the oil is discharged to the hydraulic tank 2 not only through the discharge pipe 101 and the tank pipe 103, the intended combined operation can be performed with high efficiency and high speed with little pressure loss.
When the operation signal is (4) (5) or (4) (6), the bypass valve 21 is closed and the flow control valves 16, 18, 65, 67 or 16, 20, 65, 69 are Are controlled proportionally so that the opening is proportional to the amount of operation of the operation signals (4), (5) or (4), (6), and the other flow control valves are closed (steps S20 and S21). Thus, the oil discharged from the third and fourth hydraulic pumps 3a and 3b is supplied to the operation signals (4) (5) on the rod side of the boom hydraulic cylinders 5a and 5b and the arm hydraulic cylinder 6 or the bucket hydraulic cylinder 7. ) Or (4) and (6) are combined and supplied at a flow rate allocated according to the ratio of the manipulated variables. The return oil from the bottom of the boom hydraulic cylinders 5a and 5b and the arm hydraulic cylinder 6 or bucket hydraulic cylinder 7 is discharged to the hydraulic tank 2 via the control valves 10c and 10d and 10b, 10e or 10a. At the same time, the oil is discharged to the hydraulic tank 2 through the discharge pipe 101 and the tank pipe 103 at a flow rate distributed according to the ratio of the manipulated variables (4) (5) or (4) (6). Therefore, the combined operation of lowering the boom and arm dump or bucket dump can be performed with high efficiency and high speed with little pressure loss.
Similarly, when the operation signals are (5) and (6), the bypass valve 21 is closed and the flow control valves 18, 20, 67 and 69 are operated with the operation signals (5) and (6). Proportional control is performed so that the opening degree is proportional to the amount, and the other flow control valves are closed (step S22). As a result, the oil discharged from the third and fourth hydraulic pumps 3a and 3b is disposed on the rod side of the arm hydraulic cylinder 6 and the bucket hydraulic cylinder 7 in accordance with the ratio of the operation amounts of the operation signals (5) and (6). Supplied at the allocated flow rate. The return oil from the bottom side of the arm hydraulic cylinder 6 and the bucket hydraulic cylinder 7 is discharged to the hydraulic tank 2 through the control valves 10b, 10e and 10a, and the operation amount of (5) (6) is reduced. The oil is discharged to the hydraulic tank 2 through the discharge pipe 101 and the tank pipe 103 at a flow rate distributed according to the ratio, and the combined operation of the arm dump and the bucket dump is performed with high efficiency and high speed with little pressure loss. Can do.
When the operation signals are three of the operation signals (1), (2), (3), (4), (5), and (6), they are the operation signals (1), (2), (3), and (4). (5) Different processing is performed depending on the combination of (6).

  That is, when the operation signals are (1), (2), and (3), the bypass valve 21 is closed, the flow control valves 15 and 66 are opened, and the other flow control valves are closed (step S23).

In the combined operation of the operation signals (1), (2), and (3), in order to level the excavation surface, a horizontal pulling operation is performed by raising the boom 75, clouding the arm 76, and clouding the bucket 77. is there. In this operation, the load pressures of the boom hydraulic cylinders 5a and 5b are extremely larger than the load pressures of the arm and bucket hydraulic cylinders 6 and 7. Therefore, as described above, the oil discharged from the third and fourth hydraulic pumps 3a and 3b is supplied exclusively to the bottom side of the boom hydraulic cylinders 5a and 5b, so that the boom hydraulic cylinders 5a and 5b having a large load can be reliably supplied. It is possible to supply pressure oil and to perform the leveling work smoothly.
When the operation signals are (1), (2), and (6), the bypass valve 21 is closed, the flow control valves 15, 17, 20, 66, 68, and 69 are opened, and the other flow control valves are closed. (Step S24). Thereby, the hydraulic oil discharged from the third and fourth hydraulic pumps 3a and 3b is supplied to the bottom side of the boom hydraulic cylinders 5a and 5b and the arm hydraulic cylinder 6 and supplied, and the boom hydraulic cylinders 5a and 5b are supplied. The return oil from the rod side of the arm hydraulic cylinder 6 is branched into the main pipelines 115 and 106, the branch pipelines 151B and 151D, and the discharge pipeline 101 and discharged to the hydraulic tank. Further, the oil discharged from the third and fourth hydraulic pumps 3a, 3b is supplied to the rod side of the bucket hydraulic cylinder 7 and supplied, and the return oil from the bottom side of the bucket hydraulic cylinder 7 is supplied to the control valve. The oil is discharged to the hydraulic tank 2 not only through 10 a but also through the discharge pipe 101 and the tank pipe 103. Therefore, the combined operation of raising the boom, arm cloud, and bucket dump can be performed with high efficiency and high speed with little pressure loss.
Similarly to the above, when the operation signals (1), (3), and (5) are used, the bypass valve 21 is closed and the flow control valves 15, 18, 19, 66, 67, and 70 are opened, and the other flow control is performed. The valve is closed (step S25). When the operation signals are (1), (5) and (6), the bypass valve 21 is closed, the flow control valves 15, 18, 20, 66, 67 and 69 are opened, and the other flow control valves are closed. (Step S26). When the operation signals are (2), (3), and (4), the bypass valve 21 is closed, the flow control valves 16, 17, 19, 65, 68, and 70 are opened, and the other flow control valves are closed. (Step S27). When the operation signals are (2), (4) and (6), the bypass valve 21 is closed, the flow control valves 16, 17, 20, 65, 68 and 69 are opened, and the other flow control valves are closed. (Step S28). When the operation signals are (3), (4), and (5), the bypass valve 21 is closed, the flow control valves 16, 18, 19, 65, 67, and 70 are opened, and the other flow control valves are closed. (Step S29). When the operation signals are (4), (5) and (6), the bypass valve 21 is closed, the flow control valves 16, 18, 20, 65, 67 and 69 are opened, and the other flow control valves are closed. (Step S30).

  As described above, the pressure oil supplied to the bottom side (or the rod side) of the corresponding hydraulic cylinder is supplied not only through the control valve 10 but also through the supply line 100 and the corresponding branch lines 150A to 150E. In addition, the return oil from the rod side (or bottom side) of the corresponding hydraulic cylinder is discharged to the hydraulic tank 2 not only through the control valve 10 but also through the discharge pipe line 101 and the tank pipe line 103. Therefore, the combined operation intended by the operator can be performed with high efficiency and high speed with little pressure loss.

In connection with performing various composite operations as described above, the arithmetic unit 131 associates the drive of the control valves 10a to 10f and the flow rate control valves 15, 17, 19, 65, 67, and 69 as follows. It functions as a control means to control. That is, based on a general control program stored in the ROM 37 (see FIG. 3) for controlling the control valves 10a to 10f in response to the operation signals of the operation levers 32 and 33, FIG. As shown, first, in a region where the operation amount of the operation levers 32 and 33 is relatively small (first operation amount region), only the control valves 10a to 10f stroke at a relatively small rate with respect to the increase amount of the operation amount. Then, pressure oil is supplied to the corresponding main pipelines 105 to 107 and 115 to 117. Thereafter, in a region where the operation amount of the operation levers 32 and 33 is relatively large (second operation amount region), that is, after the position where the flow rate by the control valves 10a to 10f suddenly rises as the lever operation amount increases, the control valve 10a. -F is stroked at a relatively large rate with respect to the increase amount of the operation amount, and pressure oil is supplied to the corresponding main pipelines 105-107, 115-117. At the same time, the flow control valves 15, 17, 19, 65, 67, and 69 are stroked at substantially the same rate as the control valves 10a to 10f with respect to the increase amount of the operation amount, and the operation lever-flow rate characteristic curve becomes the control valves 10a to 10f. Driven to crack with f. As a result, pressure oil is supplied to the corresponding main pipelines 105 to 107 and 115 to 117 via the corresponding branch pipelines 150A to 150F. Therefore, after the pressure oil through the control valves 10a to 10f is sufficiently supplied to the corresponding main pipelines 105, 116, 107 or 115, 106, 117, the corresponding flow control valves 15, 17, Pressure oil via 19 or 65, 57, 69 is started to be supplied to the main pipelines 105, 116, 107 or 115, 106, 117 from the branch pipelines 100A, C, F or 100B, D, E. It is possible to prevent a shock from occurring when the control valve 15, 17, 19 or 65, 57, 69 is switched.
As described above, in the present embodiment, various composite operations can be performed with high efficiency and high speed with little pressure loss by the opening / closing control of the flow rate control valves 15 to 20, 65 to 70 and the bypass valve 21. The greatest feature of the embodiment is that the total pressure loss is reduced by reducing the total length of the hydraulic circuit composed of the number of hoses and steel pipes in the super-large machine. This main effect is demonstrated in detail below.
That is, in the hydraulic excavator of this embodiment, when the hydraulic cylinders are operated in the extending direction, the hydraulic oil discharged from the hydraulic pumps 1a and 1b is transferred to the corresponding main pipelines 105, 116, and 107 via the control valve group 10. Supplied. On the other hand, at this time, the pressure oil discharged from the hydraulic pumps 3a and 3b is also supplied to the bypass valve 21 and the branch pipe through the discharge pipe 102, the supply pipe 100, and the branch pipes 150A, C, and E. The flow rate control valves 15, 17, and 19 in the paths 150 </ b> A, C, and E are appropriately adjusted and supplied to the main pipe lines 105, 116, and 107 without passing through the control valve group 10. Then, the pressure oil supplied to these main pipes 105, 116, and 107 is guided to the bottom side of the corresponding hydraulic cylinders 5a, 5b, 6, and 7 to drive the front members 75, 76, and 77, respectively. Make it work. On the other hand, the return oil on the rod side of these hydraulic cylinders 5a, 5b, 6 and 7 is discharged from the main pipelines 115, 106 and 117 to the hydraulic tank 2 through the control valve group 10, and in addition to the branch pipes. Via the control valve group 10 through the passages 151B, D, F and the discharge pipe 101, and the flow rate is appropriately adjusted by the flow control valves 66, 68, 70 of the branch pipes 151B, D, F. Without being discharged into the hydraulic tank 2.

  On the other hand, next, for example, when the hydraulic cylinders are contracted, the pressure oil discharged from the hydraulic pumps 1 a and 1 b is supplied to the corresponding main pipelines 115, 106 and 117 via the control valve group 10. At the same time, the pressure oil discharged from the hydraulic pumps 3a and 3b also flows through the discharge pipe 102, the supply pipe 100, and the branch pipes 150B, D, and F, and the flow rate thereof is changed to the bypass valve 21 and the branch. Regulated by the flow control valves 65, 67, and 69 of the pipelines 150 </ b> B, D, and F, and supplied to the main pipelines 115, 106, and 117 without passing through the control valve group 10. Then, the pressure oil supplied to these main pipelines 115, 106, 117 is guided to the rod side of the corresponding hydraulic cylinders 5a, 5b, 6, 7 to drive them, and the front members 75, 76, 77 are respectively driven. Make it work. On the other hand, at this time, part of the return oil from the bottom side of each of the hydraulic cylinders 5 a, 5 b, 6, 7 is guided from the main pipelines 105, 116, 107 to the tank pipeline 103 via the control valve group 10. At the same time, the remainder of the return oil is provided to the branch lines 151A, C, E through the main lines 105, 116, 107, the branch lines 151A, C, E, and the discharge line 101, and the flow rate thereof. It is adjusted by the flow control valves 16, 18, and 20 and led to the tank conduit 103. By using these two return routes, the hydraulic cylinders 5a, 5b, 6, and 7 are driven in the contraction direction by discharging the hydraulic oil at an extremely large flow rate from the bottom side of the hydraulic cylinders 5a, 5b, 6, and 7, and the front The members 75, 76 and 77 can be operated.

  Here, the conventional configuration is applied as a measure corresponding to the super-high flow rate of the super-large machine like this embodiment, and the control oil is simply passed through the two control valve groups after the pressure oil from the two hydraulic pumps passes through each control valve group. Even if the hydraulic pipe line from the downstream side of the valve is joined to each cylinder and finally connected to each hydraulic cylinder, the flow rate can be increased. However, in this case, the number of high-pressure line pipelines from the vehicle body side of the front device to each cylinder is 2 in the region of the front device in front of the boom cylinder. 4 each, 4 hydraulic lines to the bottom / rod side of the arm cylinder, 4 hydraulic lines to the bottom / rod side of the bucket cylinder, 4 In the area of the front device that is beyond the boom cylinder and in front of the arm cylinder, two hydraulic pipes to the bottom side and the rod side of the arm cylinder are combined to form 4 in total. A total of 8 hydraulic pipes are added to the bottom side and the rod side of the bucket cylinder and 2 side by side. In front of the space than the bucket cylinder beyond the Sunda, so that the four hydraulic line to the bottom rod side of the bucket cylinder to fit two each is rotated Yes.

On the other hand, according to the hydraulic excavator of this embodiment, the hydraulic pumps 1a, 1b and 3a, 3b, the control valves 10a to 10f, the discharge conduit 102, the tank conduit 103, and the bypass valve 21 are Provided in the vehicle body 13, main pipelines 105, 115, 116, 106, 107, 117, supply pipeline 100, discharge pipeline 101, branch pipelines 150A to F and 151A to F, flow control valves 15 to 20, and 65 to 70 and hydraulic cylinders 5a, 5b, 6 and 7 are installed in the front device 14, and at this time, the branch pipes 150A to F or 151A to F are branched from the supply pipe 100 or the discharge pipe 101. Since the position is located in the vicinity of the corresponding hydraulic cylinder, high pressure lines to the bottom and rod sides of each hydraulic cylinder, which is a particular problem when considering pressure loss, are used. The number of conduits is reduced than when applied to the conventional structure in most of the front device 14.
Specifically, since the discharge pipe 101 is a low-pressure pipe, a high-pressure line in a region (conceptually indicated by A in FIG. 1) of the front device 14 before the vicinity of the boom cylinders 5a and 5b The number of pipelines is two main pipelines 105 and 115 to the bottom and rod sides of the boom cylinders 5a and 5b, two main pipelines 116 and 106 to the bottom and rod sides of the arm cylinder 6, and a bucket cylinder. It is only necessary to turn a total of seven main pipe lines 107 and 117 to the bottom side and the rod side of 7, and one supply pipe line 100, exceeding the vicinity of the boom cylinders 5a and 5b in the front device 14. In the region before the vicinity of the arm cylinder 6 (conceptually indicated by B in FIG. 1), there are two main pipelines 116 and 106 to the bottom side and the rod side of the arm cylinder 6, and the bucket cylinder It is only necessary to turn a total of five main pipe lines 107 and 117 to the bottom side and the rod side, and one supply pipe line 100, and the bucket cylinder 7 extends beyond the vicinity of the arm cylinder 6 in the front device 14. In the area before the vicinity (conceptually indicated by C in FIG. 1), two main pipes 107 and 117 to the bottom side and the rod side of the bucket cylinder 7 and one supply pipe 100 are totaled. It is enough to just turn around.

  Therefore, the hydraulic excavator of this embodiment can reduce the number of pipes of the bottom side / rod side high-pressure line in most areas, compared with the case where the conventional structure is applied. Can be reduced.

  As described above, according to this embodiment, the number of high-pressure lines can be reduced as compared with the case where the conventional structure is applied, and accordingly, the total number of hoses (the number of steel pipes) is reduced accordingly. The extension can be shortened. Therefore, since the overall pressure loss can be reduced, energy loss can be reduced, the operating speed of the hydraulic cylinder can be increased, and work efficiency can be improved. At this time, the pressure loss can be further reduced by increasing the diameter of the hose and the steel pipe of the discharge pipe 101 which is a low-pressure line as much as possible.

  Furthermore, since the flow control valves 15-20, 65-70 and the bypass valve 21, which are single valves, are generally easier to increase in capacity than ordinary control valves, this also greatly reduces pressure loss. It becomes possible.

Further, according to the present embodiment, when the operation levers 32 and 33 are neutral, the flow control valves 15 to 20 and 65 to 70 are all closed, so that the bypass valve 21 is connected to the pumps 3 a and 3 b and the hydraulic tank 2. It can be installed in the shortest distance between them, and therefore there is an effect that the loss at the neutral time of the operation levers 32 and 33 can be minimized.
In the above embodiment, the branch pipes 150B, D, F and 151B, one side of which is connected to the main pipes 115, 106, 117 connected to the rod side of the hydraulic cylinders 5a, 5b, 6, 7, D and F are provided, and further, flow control valves 65, 66, 67, 68, 69, and 70 are provided in these branch pipes, but these are not necessarily provided. In other words, hydraulic cylinders generally have a double capacity difference between the bottom side and the rod side, so even on ultra-large machines that can achieve a very high flow rate, the rod side has a much higher flow rate than the bottom side. Is often not required. In such a case, the rod side can be used as pressure oil supply / discharge via the control valve group 10. Moreover, you may make it join the pressure oil of a 3rd and 4th hydraulic pump only to the rod side of only a desired hydraulic cylinder. Further, only the flow control valves 66, 68, 70 corresponding to the branch pipes 151B, 151D, 151F are provided on the rod side of each hydraulic cylinder, and return oil from the rod side is supplied when each hydraulic cylinder is extended. You may make it reduce the pressure loss of return oil by returning to a tank via the control valve 10 and an exhaust pipe line. Various other combinations are possible.

  In the above-described embodiment, the hydraulic oil 8 for turning is supplied and discharged with the pressure oil through the control valve 10f as usual. However, the present invention is not limited to this, and the other hydraulic cylinders 5a, 5b, 6 , 7, the pressure oil may be supplied from the supply line 100 to be joined or supplied, or the pressure oil may be joined to the discharge line 101 to be discharged. In this case, the same effect is obtained.

  Moreover, in the said embodiment, although the electromagnetic proportional valve from which a valve opening changes in proportion to a command signal was used as the flow control valves 15-20, 65-70 and the bypass valve 21, this is a simple electromagnetic on-off valve. In this case, the operation by proportional control of the solenoid valve in the above-described embodiment (see S10, S12, S13, S20, S21, and S22 in FIG. 4) cannot be obtained, but other operations can be obtained. Therefore, even in this case, the effect of reducing the pressure loss due to the hose or the steel pipe can be obtained as compared with the hydraulic drive device using the conventional structure. Also, a hydraulic pilot operated switching valve may be used instead of the solenoid valve. In this case, the control valve 10a-f, the switching valve 15-20, 65-70, and the bypass valve 21 may be switched at different timings. In this case, the pilot pipe has a larger diameter or a higher pilot pressure. As a result, the required level of responsiveness can be ensured.

  Moreover, in the said embodiment, although it described so that it might each comprise with one hose or a steel pipe etc. about the high-pressure pipe line, each was comprised with two hoses and a steel pipe under the restrictions of a high-pressure hose as mentioned above. Even in this case, it is apparent that the present invention is established.

  Further, the flow control valves 15 to 20 and 65 to 70 described above can be configured as seat valves with relatively little pressure loss with respect to the flow control switching valve 10. An example of this configuration will be described with reference to FIGS. FIG. 7 is a view extracted from FIG. 1 by taking the flow control valve 16 as an example, and FIG. 8 is a view showing the configuration of the seat valve corresponding to the configuration of FIG.

  That is, in FIG. 8, the seat valve 203 fitted in the casing 202 communicates / blocks the inlet conduit 221 communicating with the main conduit 105 and the discharge conduit 231 connected to the branch portion 101A via the check valve. Sheet section 203A, an end face 203C that receives the pressure of the discharge pipe 231; an end face 203B that receives pressure from the back pressure chamber 204 that is provided on the opposite side of the end face 203C and is formed between the casing 202; and an inlet pipe A diaphragm slit 203 </ b> D that communicates the 221 and the back pressure chamber 204 is provided. The casing 202 is formed with a pilot line 205 that allows the back pressure chamber 204 and the discharge line 231 to communicate with each other. On the pilot line 205, the flow rate of the pilot line 205 is controlled by a command signal 201. There is provided a variable restrictor 206 composed of a proportional solenoid valve to be adjusted.

  In this configuration, the pressure in the inlet pipe 221 is guided into the back pressure chamber 204 via the throttle slit 203D, and the seat valve 203 is pressed downward in the figure by this pressure, and the inlet pipe is pressed by the seat portion 203A. The passage 221 and the discharge conduit 231 are blocked. When a desired command signal 201 is given here and the variable throttle 206 is opened, the fluid in the inlet pipe 221 is discharged through the throttle slit 203D, the back pressure chamber 204, the variable throttle 206, and the pilot pipe 205. It flows out to the pipe line 231. Due to this flow, the pressure in the back pressure chamber 204 decreases due to the throttling effect of the throttling slit 203D and the variable throttling portion 206, so that the force acting on the end face 203A and the end face 203E is greater than the force acting on the end face 203B. The seat valve 203 moves upward in the drawing, and the fluid in the inlet pipe 221 flows out to the discharge pipe 231. At this time, if the seat valve 203 is excessively raised, the throttle opening of the throttle slit 203D is increased, whereby the pressure in the back pressure chamber 204 is increased and the seat valve 203 is moved downward in the drawing.

  In this way, the seat valve 203 stays at the throttle opening position of the throttle slit 203D corresponding to the throttle opening degree of the variable throttle section 206, so that the discharge pipe from the desired inlet line 221 is based on the command signal 201. The fluid flow rate to the path 231 can be controlled.

  Furthermore, although the above embodiment is an embodiment in which the present invention is applied to a hydraulic excavator, it can be widely applied to construction machines including other swivels and a front device.

It is the figure which showed the hydraulic circuit showing the structure of the hydraulic drive unit with which the hydraulic working machine by one Embodiment of this invention is equipped with the control apparatus. It is a side view showing the whole structure of the hydraulic shovel as one Embodiment of the hydraulic working machine of this invention which is a drive object of the hydraulic drive device of FIG. It is a functional block diagram showing the detailed function of the arithmetic unit shown in FIG. It is a flowchart showing the control function of the arithmetic unit shown in FIG. It is a flowchart showing the control function of the arithmetic unit shown in FIG. It is a figure which shows an example of an operation lever-flow volume characteristic. It is detail drawing showing the structure of a flow control valve. It is the figure which showed the structure of the seat valve corresponding to the structure of FIG.

Explanation of symbols

1a 1st pump 1b 2nd pump 3a 3rd pump (other hydraulic pumps)
3b 4th pump (other hydraulic pumps)
5a, b Hydraulic cylinder 6,7 Hydraulic cylinder 10a-f Control valve (flow control switching valve)
13 Body (work machine body)
14 Front device 15, 17, 19 Flow control valve (first flow control means)
16, 18, 20 Flow control valve (second flow control means)
21 Bypass valve 65, 67, 69 Flow control valve (first flow control means)
66, 68, 70 Flow control valve (second flow control means)
75 Boom 76 Arm 77 Bucket 100 Supply line (second connection line)
101 Discharge pipe (third connection pipe)
103 Tank pipeline 105 Main pipeline (first connection pipeline)
106 Main pipeline (first connecting pipeline)
107 Main pipeline (first connecting pipeline)
115 Main pipeline (first connecting pipeline)
116 Main pipeline (first connecting pipeline)
117 Main pipeline (first connecting pipeline)
131 Calculators 150A-F Branch pipeline (first pipeline)
151A-F Branch pipe (second pipe)

Claims (3)

In a hydraulic working machine including a vehicle body that is a working machine body, and a front device configured by a plurality of front members that are pivotably connected to the working machine body in the vertical direction,
At the vehicle body side, at least one hydraulic pump, a plurality of flow rate control switching valves for controlling the pressure oil discharged from the hydraulic pump, at least one other hydraulic pump, and the other hydraulic pump are discharged. And a discharge pipe through which the pressurized oil is guided ,
The front device side includes a plurality of hydraulic cylinders that respectively drive the plurality of front members, and a plurality of hydraulic cylinders that respectively connect either the bottom side or the rod side of the hydraulic cylinder corresponding to the flow rate control switching valve. A first connection line; a second connection line connected on one side to the discharge line of the other pump; a plurality of branch points provided on the other side of the second connection line; A plurality of first pipes each connected to one of the points and connected to at least one of the plurality of first connection pipes connected to at least the bottom side of the hydraulic cylinder; Each of the plurality of first members is provided on each of the plurality of first pipes so as to be located on the bottom side of the corresponding hydraulic cylinder with respect to the branch point. A plurality of first flow rate control means for controlling the flow of pressure oil from the pump toward the bottom side of the corresponding hydraulic cylinder ;
Hydraulic work characterized in that, on the front device side, the pressure oil from the other hydraulic pump is guided to the bottom side of a plurality of hydraulic cylinders via a second connection pipe which is a common supply line. machine. The hydraulic working machine according to claim 1,
On the vehicle body side, a hydraulic tank and a tank conduit for guiding pressure oil to the hydraulic tank are provided ,
The front device side includes a third connection pipe having one side connected to the tank pipe, a plurality of branch points provided on the other side of the third connection pipe, and one side being one of the branch points. A plurality of second pipes each connected to one of the plurality of third connection pipes connected to at least the bottom side of the hydraulic cylinder;
Each of the plurality of second pipes is installed on one of the plurality of front members and is located on the bottom side of the corresponding hydraulic cylinder with respect to the branch point. and a plurality of second flow control means for controlling the flow of hydraulic fluid toward said third connecting line is provided,
A hydraulic work characterized in that, on the front device side, the pressure oil from the bottom side of the plurality of hydraulic cylinders is guided to a pre-hydraulic storage tank through a third connection pipe which is a common discharge pipe. machine. In a hydraulic working machine including a vehicle body that is a working machine body, and a front device configured by a plurality of front members that are pivotably connected to the working machine body in the vertical direction,
At the vehicle body side, at least one hydraulic pump, a plurality of flow rate control switching valves for controlling the pressure oil discharged from the hydraulic pump, at least one other hydraulic pump, and the other hydraulic pump are discharged. and a discharge line pressure oil is guided, and the hydraulic tank, and a tank line that leads pressure oil to the hydraulic tank is provided,
The front device side includes a plurality of hydraulic cylinders that respectively drive the plurality of front members, and a plurality of hydraulic cylinders that respectively connect either the bottom side or the rod side of the hydraulic cylinder corresponding to the flow rate control switching valve. A first connection line, a second connection line connected on one side to the discharge line, a plurality of branch points provided on the other side of the second connection line, and one side being one of the branch points A plurality of first pipes each connected to one of the plurality of first connection pipes connected to at least the bottom side of the hydraulic cylinder, and the plurality of front pipes. Each of the plurality of first pipes installed on one of the members and positioned on the bottom side of the corresponding hydraulic cylinder side with respect to the branch point. A plurality of first flow rate controls that allow the flow of pressure oil toward the hydraulic cylinder through a variable throttle that controls the throttle amount to a desired amount, and block the flow of pressure oil from the hydraulic cylinder toward the other hydraulic pump. Means, a third connection line connected on one side to the tank line, a plurality of branch points provided on the other side of the third connection line, and one side connected to one of the branch points. A plurality of second pipes connected to one of the plurality of third connection pipes connected to at least the bottom side of the hydraulic cylinder, and one of the plurality of front members. Are installed in the plurality of second pipelines so as to be located on the bottom side of the corresponding hydraulic cylinders with respect to the branch point, and are directed from the hydraulic cylinders to the third connection pipelines. With allowable via the variable throttle for controlling the flow of hydraulic fluid to a desired aperture size, provided a plurality of second flow control means for interrupting the flow of pressure oil flowing from the third connecting pipeline to the hydraulic cylinder,
On the front device side, the pressure oil from the other hydraulic pumps is guided to the bottom side of the plurality of hydraulic cylinders via the second connection pipe which is a common supply line, and from the bottom side of the plurality of hydraulic cylinders. A hydraulic working machine configured to guide pressure oil to the hydraulic tank via a third connection pipe which is a common discharge pipe .

Images