JP2004019810A - Directional switching control valve device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a directional switching control valve device, controlling the flow according to the respective load characteristics of a plurality of actuators and having a compact valve structure in a hydraulic system in which a confluecne circuit and a precedence circuit can be realized in simple constitution by a closed center circuit and the precedence and metering characteristic in compound operation can be controlled independently. <P>SOLUTION: A first and second pump passages 301, 302 are formed in parallel at the substantially same position in a housing 207, directional switching valve spools 331 to 337 are disposed at positions of height away from the first and second pump passages 301, 302, auxiliary poppet valves 442a, 442b to 447a, 447b are disposed at positions crossing the first and second pump passages 301, 302, and bleed valve spools 811 to 814, 821 to 824 are disposed in zigzag to the directional switching valve spools 331, 332, 333. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a directional control valve device mounted on a construction machine such as a hydraulic excavator and used in a hydraulic system that drives a plurality of actuators with a plurality of hydraulic pumps.
[0002]
[Prior art]
Hydraulic systems for driving a plurality of actuators with a plurality of hydraulic pumps on a construction machine such as a hydraulic shovel or the like include a so-called open center circuit as described in Japanese Patent Publication No. 2-164416, and Japanese Patent Application Laid-Open No. 4-194405. There is a circuit called a closed center circuit as described in (1).
[0003]
The open center circuit has a center bypass line that connects the discharge line of the hydraulic pump to the tank for each hydraulic pump, and a plurality of directional control valves are arranged in series in the center bypass line. The oil discharged from the pump is returned to the tank through the center bypass line and the center bypass throttle of the directional control valve. When each directional control valve is operated, the center bypass throttle is throttled according to the operation amount (bleed flow control), and the hydraulic pump is operated. To supply pressure oil to each actuator by increasing the discharge pressure.
[0004]
In the open center circuit, by providing a priority circuit called a tandem connection or a merging circuit for merging the discharge oils of a plurality of hydraulic pumps, the combined operability and independence when simultaneously driving a plurality of actuators is maintained. When operating each directional control valve, the opening area of the meter-in throttle is increased according to the stroke (operating amount) of the directional control valve, the opening area of the center bypass throttle is reduced, and the discharge pressure of the hydraulic pump is controlled by bleed flow control. , The flow rate is controlled in accordance with the load characteristics of the actuator, and the bleed flow rate control at the time of starting the actuator provides a cushioning effect against hydraulic pressure fluctuations, thereby preventing a sudden increase in pressure.
[0005]
The closed center circuit is a circuit having no center bypass line. As described in Japanese Patent Application Laid-Open No. 4-194405, each directional control valve is connected in parallel to a hydraulic pump, and a difference between a pump pressure and a load pressure is determined. By using a load sensing system that controls the pressure at a constant level, the pump discharge flow rate can be reduced when each directional control valve is neutral, or the pump discharge flow rate can be increased when operating each directional control valve to supply pressure oil to each actuator. I have.
[0006]
In addition, a pressure compensating valve is provided upstream or downstream of each directional control valve, and the pressure compensating valve maintains the differential pressure across the meter-in throttle of each directional control valve, thereby achieving combined operability and each actuator at that time. And the flow characteristics (metering characteristics) of each actuator are ensured.
[0007]
As a closed center circuit hydraulic system, there is one proposed in Japanese Patent Application Laid-Open No. 9-79212. In this hydraulic system, at least one of a plurality of closed center type directional switching valves (first directional switching valve) is connected to first and second two hydraulic pumps, and the other one (second directional switching valve) is connected. Switching valve) is connected to at least the first hydraulic pump, a first auxiliary valve is disposed on a feeder line of the first directional switching valve on the first hydraulic pump side, and a second auxiliary valve is disposed on a feeder line of the second hydraulic pump side. An auxiliary valve is provided to control the opening and closing of the first and second auxiliary valves and to change the degree of throttle (opening area) to provide the functions of a merging circuit and a priority circuit. Further, the discharge line of the first hydraulic pump is connected to the tank via a bypass line in which the first bleed valve is disposed, and the discharge line of the second hydraulic pump is connected to the tank through a bypass line in which the second bleed valve is disposed. And the bleed valves are operated in an electro-hydraulic manner in conjunction with the operation of the related directional control valves so that the same bleed flow control as the center bypass throttle of each directional control valve in the open center circuit can be performed. I have.
[0008]
Here, as control means for the first and second bleed valves, there are provided means for detecting operating pilot pressure of the first and second directional control valves, a controller, and a proportional solenoid valve. An opening area characteristic of the first bleed valve and an opening area characteristic of the second bleed valve with respect to an operation amount (operating pilot pressure) of the second direction switching valve are set. When the operating levers of the first and second directional control valves are operated and the operating pilot pressure is detected, the controller determines the opening area of the first or second bleed valve corresponding to the operating pilot pressure, and determines the opening area. The corresponding proportional solenoid valve is driven to obtain the area. The output pressure of the proportional solenoid valve is applied to the first or second bleed valve to drive the first or second bleed valve.
[0009]
[Problems to be solved by the invention]
However, the above prior art has the following problems.
[0010]
In the conventional open center circuit, by providing the priority circuit and the merging circuit as described above, the combined operability and the independence of each actuator are maintained, and the load on the actuator is controlled by the bleed flow rate control by the center bypass throttle of the directional control valve. It has a flow control function according to its characteristics and a cushioning effect against hydraulic fluctuations, and is currently widely used as a product.
[0011]
However, in the open center circuit, each directional control valve requires a center bypass line passage (center bypass restrictor) and one actuator needs to be provided with a plurality of directional control valves. There is a problem that the structure is complicated and large. In addition, since the priority circuit is formed by the center bypass line, the priority level and the metering characteristics cannot be independently adjusted during the combined operation of driving a plurality of actuators at the same time, and the controllability is limited.
[0012]
Since the closed center circuit does not require a center bypass line, and usually only needs to provide one directional control valve for one actuator, the valve structure is not large as compared with the open center circuit. However, since it is basically a parallel circuit, it is difficult to incorporate a priority circuit and a merging circuit when multiple hydraulic pumps are used and it is attempted to increase the output of the actuator. There is a problem that it is difficult to maintain. Further, in the closed center circuit, the cushion performance against the fluctuation of the hydraulic pressure as in the open center circuit cannot be obtained, and the discharge pressure of the hydraulic pump is apt to change greatly, and there is a problem in operability.
[0013]
The hydraulic system described in Japanese Patent Application Laid-Open No. 9-79212 is a closed center circuit hydraulic system that realizes a merging circuit and a priority circuit with a simple structure, and separately controls an auxiliary valve and a bleed valve to perform a combined operation. The priority and metering characteristics can be adjusted independently. Further, by operating the first and second bleed valves like the center bypass throttles of the respective directional control valves in the open center circuit, a flow control function according to the load characteristics of the actuator and a cushioning action against hydraulic fluctuations are obtained. I have.
[0014]
However, in the hydraulic system described in Japanese Patent Application Laid-Open No. 9-79212, one bleed valve is provided for a plurality of directional control valves, and a function similar to a center bypass throttle for each directional control valve in an open center circuit will be provided. The control amount of the bleed valve must be changed according to the load characteristics of the actuators related to the plurality of directional control valves. In this case, the bleed valve is actually controlled to match the load characteristics of each of the multiple actuators due to factors such as too complicated calculation by the controller, performance variations between products, and response delay of electro-hydraulic control. It is extremely difficult to do so, and the hydraulic system has not yet been put to practical use.
[0015]
SUMMARY OF THE INVENTION An object of the present invention is to provide a hydraulic system that can realize a merging circuit and a priority circuit with a simple configuration in a closed center circuit and that can independently control the priority and metering characteristics in a combined operation. An object of the present invention is to provide a directional switching valve device that can perform flow control according to the load characteristics of each actuator and that is compact without a large valve structure.
[0016]
[Means for Solving the Problems]
(1) In order to achieve the above object, the present invention is directed to a first and a second pump passages arranged side by side at substantially the same height, and a height separated from the first and the second pump passages. And first and second directional control valve spools arranged side by side in a direction crossing these pump passages at the first position, and connecting the first and second pump passages to a pump port of the first directional control valve spool. The first and second feeder passages are disposed in a direction crossing the first and second pump passages, respectively, and supplied from the first and second pump passages to the first and second feeder passages. First and second auxiliary valve poppet valves for respectively controlling the flow of pressure oil in a supplementary manner, and a third feeder passage connecting the first pump passage to a pump port of the second directional control valve spool. , The first pump passage A third auxiliary valve poppet valve that is arranged in a transverse direction and that auxiliary controls the flow of the pressure oil supplied from the first pump passage to the third feeder passage. One end of the first and second directional control valve spools is disposed at a height position opposite to the first and second pump passages in the same direction as the first and second pump passages with the first and second directional control valve spools interposed therebetween. Are connected to the first and second pump passages, the first and second bypass passages are connected to the tank passage at the other end, and are arranged side by side in a direction crossing the first bypass passage. First and second bleed valve spools that decrease the opening area as the operation strokes of the first and second directional control valve spools increase, and are disposed in a direction crossing the second bypass passage, the first direction Operation of switching valve spool A third bleed valve spool for decreasing the opening area as the stroke increases, wherein the first and second bleed valve spools are provided on the first and second directional control valve spools on the first bypass passage side. On the other hand, the third bleed valve spool is staggered with respect to the first and second direction switching valve spools on the side of the second bypass passage.
[0017]
By providing the first and second pump passages, the first and second directional control valve spools, the first to third feeder passages, and the first to third auxiliary valve poppet valves in this manner, Japanese Patent Application Laid-Open No. 9-79212 is disclosed. As described in Japanese Patent Application Laid-Open Publication No. H11-157, a merger circuit and a priority circuit can be realized with a simple configuration by a closed center circuit, and the priority degree and metering characteristics in a combined operation can be independently controlled.
[0018]
Further, by disposing the first and second bleed valve spools in the first bypass passage and disposing the third bleed valve spool in the second bypass passage, the first directional control valve spool is operated when the first directional control valve spool is operated. By operating the first and second bleed valve spools and operating the third bleed valve at the time of operating the second directional valve spool, the bleed is individually performed on each of the first and second directional valve spools. Flow control can be performed, flow control can be performed in accordance with the load characteristics of the actuator, and a cushion effect against hydraulic pressure fluctuation can be obtained.
[0019]
Further, the first and second bypass passages are connected to the first and second pump passages at heights opposite to the first and second pump passages with respect to the first and second directional control valve spools. The first and third bleed valve spools are arranged side by side in the direction crossing the first and second bypass passages, and the first and second bleed valve spools are arranged on the first bypass passage side. By arranging the first and second directional control valve spools in a staggered manner, and arranging the third bleed valve spool on the bypass passage side in a staggered manner with respect to the first and second directional control valve spools, Since the distance in the height direction between the valve spool and the bleed valve spool is shortened, even if the number of bleed valve spools increases, various valve elements can be rationally arranged within the limited volume of the housing without waste, Set the valve structure to It can be in the Pact.
[0020]
(2) In the above (1), preferably, the first to third bleed valve spools have, at both ends thereof, a pressure receiving portion to which a pilot pressure signal for causing the corresponding directional control valve spool to stroke is guided. Activated by the pilot pressure signal.
[0021]
Accordingly, the first to third bleed valve spools are directly hydraulically driven by the same pilot pressure signal as operating the corresponding directional control valve spool, so that the first to third bleed valves are operated without delay. And a good flow control function can be obtained.
[0022]
(3) In the above (1), preferably, the first and second auxiliary members are located at a height opposite to the first directional control valve spool across the first and second pump passages. First and second auxiliary valve pilot spools arranged in the same direction as the valve poppet valve, and at a height opposite to the second directional control valve spool across the first and second pump passages; A third auxiliary valve pilot spool disposed in the same direction as the third auxiliary valve poppet valve;
[0023]
Accordingly, the auxiliary valve pilot spool can be rationally disposed in the same housing without waste, and the valve structure can be made compact.
[0024]
(4) Further, in the above (1), preferably, the first and second bypass passages are arranged at substantially the same height position as the first and second bypass passages and downstream of the first and second bypass passages, respectively. The apparatus further includes a second pump control valve.
[0025]
Thus, the first and second pump control valves can be rationally arranged without waste in the same housing, and the valve structure can be made compact.
[0026]
(5) Further, in order to achieve the above object, the present invention provides a method in which the first and second pump passages arranged at substantially the same height are separated from the first and second pump passages. First and second directional control valve spools arranged side by side in a direction crossing these pump passages at a raised position, and a pump port of the first directional control valve spool connected to the first and second pump passages. And a first feeder passage communicating with the first feeder passage and a first feeder passage arranged in a direction crossing the first and second pump passages, and supplying the first and second feeder passages from the first and second pump passages. First and second auxiliary valve poppet valves for respectively controlling the flow of pressurized oil to be supplied, and a first and a second pump passage connecting the first and second pump passages to a pump port of the second directional control valve spool. Third and fourth feeder passages; The first and second pump passages are respectively arranged in a direction crossing the first and second pump passages, and the flow of the pressure oil supplied from the first and second pump passages to the third and fourth feeder passages is respectively auxiliary controlled. A directional switching valve device comprising a third and a fourth auxiliary valve poppet valve, wherein a height position on the opposite side of the first and second pump passages across the first and second directional switching valve spools. The first and second pump passages are arranged in the same direction as the first and second pump passages, and have one end connected to the first and second pump passages and the other end connected to the tank passage. First and second bleed valves arranged side by side in a direction crossing the first bypass passage and decreasing an opening area as an operation stroke of the first and second directional control valve spools increases; A spool and the second Third and fourth bleed valve spools arranged side by side in a direction crossing the bypass passage, the opening areas decreasing as the operation strokes of the first and second directional control valve spools increase; And a second bleed valve spool is arranged on the first bypass passage side in a zigzag manner with respect to the first and second directional control valve spools, and the third and fourth bleed valve spools are arranged in the second bypass. It is assumed that the first and second directional control valve spools are staggered on the passage side.
[0027]
Thus, as described in Japanese Patent Application Laid-Open No. 9-79212, a merger circuit and a priority circuit including a second directional control valve spool can be realized with a simple configuration in a closed center circuit, and a combined operation can be realized. The priority and the metering characteristics can be controlled independently.
[0028]
Further, as described in the above (1), the flow rate can be controlled according to the load characteristics of each of the plurality of actuators in such a hydraulic system, and the valve structure can be made compact.
[0029]
(6) Further, in order to achieve the above object, the present invention is directed to a first and a second pump passages arranged side by side at substantially the same height, and separated from the first and the second pump passages. A plurality of directional control valve spools including directional control valve spools for right traveling, left traveling, turning, bucket, boom, and arm, which are arranged side by side in a direction traversing these pump passages at the height position. A first feeder passage connecting the first pump passage to a pump port of the right-running direction switching valve spool, and a first feeder passage connecting the first and second pump passages to the left-running direction switching valve spool. Second and third feeder passages communicating with a pump port; a fourth feeder passage communicating the second pump passage with a pump port of the directional valve spool for turning; and the first and second feeder passages. In front of the pump passage Fifth and sixth feeder passages communicating with the pump ports of the directional valve spools for buckets, and seventh and sixth feeders communicating the first and second pump passages with the pump ports of the directional valve spools for the boom. Eighth also a feeder passage, ninth and tenth feeder passages connecting the first and second pump passages to a pump port of a directional valve spool for the arm, and first and second pump passages. And second auxiliary valve poppets respectively arranged in a direction crossing the first and second pump passages for supplementarily controlling the flow of pressure oil supplied from the first and second pump passages to the second and third feeder passages, respectively. And a valve disposed in a direction crossing the first and second pump passages, respectively, to deflect the flow of the pressure oil supplied from the first and second pump passages to the fifth and sixth feeder passages. Third and fourth auxiliary valve poppet valves which are controlled in an auxiliary manner, and which are arranged in a direction crossing the first and second pump passages, respectively, from the first and second pump passages. And a fifth and a sixth auxiliary valve poppet valves for respectively controlling the flow of the pressure oil supplied to the feeder passages of the first and second pump passages in a direction crossing the first and second pump passages, respectively. A directional switching valve device comprising: a seventh and an eighth auxiliary valve poppet valves for auxiliary controlling the flow of the pressure oil supplied from the second pump passage to the ninth and tenth feeder passages, respectively. The first and second directional control valve spools are arranged in the same direction as the first and second pump passages at a height position opposite to the first and second pump passages with the first and second directional control valve spools therebetween. Sides of the first and second pump passages The first and second bypass passages connected to the tank passage at the other end side are arranged side by side in a direction crossing the first bypass passage, and the right traveling, the left traveling, the turning, The opening area of the four directional control valve spools including at least the directional control valve for right running among the directional control valve spools for the bucket, the boom, and the arm decreases as the operation stroke of each directional control valve spool increases. The first to fourth bleed valve spools to be operated are arranged side by side in the direction crossing the second bypass passage, and the direction switching for the right running, the left running, the turning, the bucket, the boom, and the arm is performed. Regarding four directional control valve spools including at least the directional directional control valve for turning of the valve spools and the remaining directional control valve spools not included in the four directional control valve spools, A fifth to an eighth bleed valve spool for decreasing the opening area as the operation stroke of the direction switching valve spool increases, wherein the first to fourth bleed valve spools are connected to the right side on the first bypass passage side. The three directional control valve spools of the directional control valve spools for traveling, left traveling, turning, bucket, boom, and arm are arranged in a staggered manner, and the fifth to eighth bleed valve spools are arranged. Three directional control valve spools out of the directional control valve spools for the right running, the left running, the turning, the bucket, the boom, and the arm on the second bypass passage side; I do.
[0030]
As a result, as described in Japanese Patent Application Laid-Open No. 9-79212, a merging circuit and a priority circuit can be realized with a simple configuration in a closed center circuit used in a hydraulic system of a hydraulic shovel, and the priority degree in a combined operation can be improved. Metering characteristics can be controlled independently.
[0031]
Further, as described in the above (1), the flow rate can be controlled according to the load characteristics of each of the plurality of actuators in such a hydraulic system, and the valve structure can be made compact.
[0032]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[0033]
FIG. 1 is a hydraulic circuit diagram showing a hydraulic system using a direction switching valve device according to one embodiment of the present invention, in which the present invention is applied to a hydraulic shovel.
[0034]
In FIG. 1, a hydraulic system according to the present embodiment includes first and second two variable displacement hydraulic pumps 1a and 1b, and regulators 2a and 2b for controlling the displacements of the hydraulic pumps 1a and 1b, respectively. A plurality of actuators including a boom cylinder 3, an arm cylinder 4, a spare actuator 69, a bucket cylinder 5, a swing motor 6, and first and second traveling motors 7, 8, and first and second hydraulic pumps 1a, 1b. Boom cylinder 3, arm cylinder 4, spare actuator 69, closed center type boom directional switching valve 9, arm directional switching valve 10 for controlling the flow rate of hydraulic oil supplied to bucket cylinder 5, respectively, The directional control valve 11 for the bucket, the directional control valve 70 for the spare, and the second hydraulic pump 1 b are connected to Flow rate of the pressure oil supplied to the first traveling motor 7 which is connected to the closed center type turning direction switching valve 12 for controlling the flow rate of the pressure oil to be supplied and the first and second hydraulic pumps 1a and 1b. And a closed center type directional control valve 13 connected to the first hydraulic pump 1a for controlling the flow rate of pressure oil supplied to the second traveling motor 8. And two traveling direction switching valves 14.
[0035]
The boom, arm, bucket, turning, first and second traveling, and spare directional switching valves 9 to 14, 70 are respectively provided at both ends of the spool with pilot hydraulic drive units 9da, 9db; 10da, 10db; 12da, 12db; 13da, 13db; 14da, 14db; 70da, 70db. Pilot operation valves having pilot pressure signals 92a, 92b; 102a, 102b; 112a, 112b; 122a, 122b; 132a, 132b. 142a, 142b; 702a, 702b.
[0036]
The boom, arm, bucket, swivel, first and second traveling, and spare directional control valves 9 to 14, 70 are respectively provided with pump ports 9p, 10p, 11p, 12p, 13p, 14p, 70p. , Tank ports 9t, 10t, 11t, 12t, 13t, 14t, 70t, two actuator ports 9a, 9b; 10a, 10b; 11a, 11b; 12a, 12b; 13a, 13b; 14a, 14b; 70a, 70b. The tank port is connected to the tank 29, and the actuator port is connected to a corresponding hydraulic actuator. Counterbalance valves 27, 28 are provided between the pump ports 13a, 13b; 14a, 14b of the first and second traveling direction switching valves 13, 14 and the first and second traveling motors 7, 8, respectively. Have been.
[0037]
The pump port 9p of the boom directional control valve 9 is connected to the first and second hydraulic pumps 1a via the first and second pump lines 30a, 30b and the first and second boom feeder lines 93a, 93b. , 1b, the pump port 10p of the arm directional switching valve 10 is connected to the first and second pump lines 30a, 30b and the first and second arm feeder lines 103a, 103b. The pump port 11p of the bucket directional control valve 11 is connected to the first and second pump lines 30a and 30b and the first and second bucket feeder lines 113a and 113b. The first and second hydraulic pumps 1a and 1b are connected to each other, and the pump port 70p of the spare directional control valve 70 is connected to the first and second pump lines 30a and 30a. 0b and the first and second hydraulic pumps 1a and 1b via the first and second spare feeder lines 703a and 703b, and the pump port 12p of the turning direction switching valve 12 is connected to the second pump line 30b. The pump port 13p of the first traveling direction switching valve 13 is connected to the first and second pump lines 30a and 30b and the first and second pump lines 13a and 13b. Are connected to the first and second hydraulic pumps 1a and 1b via the traveling feeder lines 133a and 133b, respectively. The pump port 14p of the second traveling direction switching valve 14 is connected to the first pump line 30a and the traveling feeder. It is connected to the first hydraulic pump 1a via a line 143a.
[0038]
The first and second boom auxiliary valves 91a and 91b are provided on the first and second boom feeder lines 93a and 93b, respectively, and the first and second arm feeder lines 103a and 103b, the first and second boom feeder lines are provided. The same applies to the first and second arms for the second bucket feeder lines 113a and 113b, the first and second spare feeder lines 703a and 703b, and the first and second traveling feeder lines 133a and 133b. Auxiliary valves 101a and 101b, first and second bucket auxiliary valves 111a and 111b, first and second arm auxiliary valves 701a and 701b, and first and second travel auxiliary valves 131a and 131b are provided. ing. These auxiliary valves are driven by control pressures generated by proportional solenoid valves 31a, 31b; 32a, 32b; 33a, 33b; 34a, 34b;
[0039]
The auxiliary valves 91a, 91b; 101a, 101b; 111a, 111b; 131a, 131b; 701a, 701b are poppet valve type valves, and prevent backflow of pressure oil to the first and second hydraulic pumps 1a, 1b. Backflow prevention function and a variable resistance function for supplementarily controlling the flow of the pressure oil supplied from the first and second hydraulic pumps 1a and 1b. The variable resistance function includes the first and second hydraulic pumps. A flow shutoff function for selectively shutting off the flow of the pressure oil from the hydraulic pumps 1a and 1b is included. The principle of a poppet valve having a variable resistance function is known (see, for example, Japanese Patent Publication No. 58-501781), and the auxiliary valve of the present embodiment is an application of this poppet valve. Details of the auxiliary valve will be described later.
[0040]
The turning feeder line 123b is provided with a load check valve 16 for preventing pressure oil from flowing backward from the turning motor 6 to the second hydraulic pump 1b when the load of the turning motor 6 is high, and the second bucket feeder is provided. A fixed throttle 17 for limiting the bucket speed is provided on the line 113b on the upstream side of the second auxiliary valve 111b.
[0041]
Relief lines 72a and 72b branch off from the first and second pump lines 30a and 30b, respectively. Check valves 73a and 73b are provided in the relief lines 72a and 72b, and a line 74 is provided downstream of the check valves 73a and 73b. The line 74 is provided with a main relief valve 75 for regulating the maximum pressure of the discharge oil of the first and second hydraulic pumps 1a and 1b.
[0042]
In addition, first and second bypass lines 25a and 25b connecting the first and second pump lines 30a and 30b to the tank 29 are branched from the first and second pump lines 30a and 30b, respectively. The first to fourth bleed valves 81 to 84 are installed in the bypass line 25a, and the fifth to eighth bleed valves 85 to 88 are installed in the second bypass line 25b. A pump control valve 77 is provided downstream of the first to fourth bleed valves 81 to 84 in the first bypass line 25a, and a fifth to eighth bleed valve 85 to 85 in the second bypass line 25b. A pump control valve 78 is provided downstream of 88. Details of the bleed valves 81 to 88 and the pump control valves 77 and 78 will be described later.
[0043]
FIG. 2 shows an operation system of the excavator. The hydraulic shovel is provided with an operating lever device 19 as operating means for a boom and a bucket, an operating lever device 20 as operating means for an arm and a turn, and an operating pedal device 21 for left and right running as operating means for running. , 22 are provided, and an operation lever device 23 is provided as spare operation means.
[0044]
The operation lever device 19 has an operation lever 19a that can be operated in universal directions including front and rear, left and right, and when the operation lever 19a is operated in front and rear directions, a pilot pressure signal 92a for raising the boom and a boom according to the operation direction and operation amount. When the lowering pilot pressure signal 92b is generated and the operation lever 19a is operated in the left-right direction, the pilot pressure signal 112a of the bucket cloud and the pilot pressure signal 112b of the bucket dump are generated according to the operation direction and the operation amount. The operation lever device 20 also has an operation lever 20a that can be operated in universal directions including front and rear, left and right, and when the operation lever 20a is operated in the left and right directions, the pilot pressure signal 102a of the arm cloud and the arm are controlled according to the operation direction and operation amount. When a pilot pressure signal 102b for the dump is generated and the operation lever 20a is operated in the front-rear direction, a pilot pressure signal 122a for turning right and a pilot pressure signal 122b for turning left are generated according to the operation direction and the operation amount.
[0045]
When the operating pedal device 21 for the left running depresses the operating pedal 21a back and forth, the left running forward pilot pressure signal 132a and the left running reverse pilot pressure signal 132b are generated in accordance with the stepping direction and the stepping amount, and the right running. When the operation pedal 22a is depressed back and forth, the operation pedal device 22 generates a pilot pressure signal 142a for rightward traveling forward and a pilot pressure signal 142b for rightward traveling backward according to the depression direction and the amount of depression. When operating the operation lever 23a, the spare operation lever device 23 generates pilot pressure signals 702a and 702b according to the operation direction and the operation amount.
[0046]
The high pressure side of the arm cloud pilot pressure signal 102a and the spare pilot pressure signal 702a is selected by the shuttle valve 24a and output as the pilot pressure signal 711a, and the arm dump pilot pressure signal 102b and the spare pilot pressure signal 702b. Is selected by the shuttle valve 24b and output as the pilot pressure signal 711b, and the high pressure side of the turning right pilot pressure signal 122a and the spare pilot pressure signal 702a is selected by the shuttle valve 24c and output as the pilot pressure signal 712a. The high pressure side of the turning left pilot pressure signal 122b and the spare pilot pressure signal 702b is selected by the shuttle valve 24d and output as the pilot pressure signal 712b, and the boom raising pilot pressure signal is output. High-pressure side of the pilot pressure signals 112a of 2a and bucket crowding is selected by the shuttle valve 24e, it is outputted as a pilot pressure signal 713a.
[0047]
FIG. 3 shows proportional solenoid valves 31a, 31b; 32a, 32b; 33a, 33b; 33a, 33b; 34a, 34b; 35a, which are driving means for the auxiliary valves 91a, 91b; 101a, 101b; 111a, 111b; 131a, 131b; , 35b.
[0048]
101a, 101b; 111a, 111b; 131a, 131b; pilot pressure sensors 41a, 41b for detecting pressures of pilot pressure signals supplied to the directional control valves 9 to 14, 70 as control means of 701a, 701b. 42a, 42b; 43a, 43b; 44a, 44b; 45a, 45b; 46a, 46b; 47a, 47b, and a controller 25. The controller 25 performs a predetermined calculation based on signals from the pilot pressure sensors. And outputs a command signal to each of the proportional solenoid valves 31a, 31b to 35a, 35b. The proportional solenoid valves 31a, 31b to 35a, 35b are operated by the command signal, and control the auxiliary valves 91a, 91b; 101a, 101b; 111a, 111b; 131a, 131b; 701a, 701b.
[0049]
The controller 25 includes an input unit 25a for A / D converting and inputting detection signals of the pilot pressure sensors 41a, 41b to 47a, 47b, a storage unit 25b storing preset characteristics, and the storage unit 25b. And a predetermined operation is performed to calculate a command signal for the proportional solenoid valves 31a, 31b to 35a and 35b. An output unit 25d that converts the command signal calculated by the calculation unit 25c into a drive signal and outputs the drive signal And
[0050]
FIG. 4 shows an external appearance of a hydraulic shovel on which the above-described hydraulic system is mounted. The hydraulic excavator includes a boom 50 driven by the boom cylinder 3, an arm 51 driven by the arm cylinder 4, a bucket 52 driven by the bucket cylinder 5, an upper swing body 53 driven by the swing motor 6, The boom 50, the arm 51, and the bucket 52 are provided with a front working machine 56 that works at the front of the upper revolving unit 53, and includes left and right traveling devices 54 and 55 driven by the first and second traveling motors 7 and 8. The left and right traveling devices 54 and 55 constitute a lower traveling body 57. When performing an operation using an attachment other than the bucket, for example, a crushing operation, the bucket 52 is removed, and an attachment having a spare actuator 69 is attached, and the operation is performed.
[0051]
When controlling the auxiliary valves 91a and 91b; 101a and 101b; 111a and 111b; 131a and 131b; 701a and 701b, the traveling devices 54 and 55 and the turning devices are controlled based on detection signals of the pilot pressure sensors 41a, 41b to 47a and 47b. The operating states of the body 53, the boom 50, the arm 51, and the bucket 52 are determined, and the operating states of the auxiliary valves 91a, 91b; 101a, 101b; 111a, 111b; 131a, 131b; , Or fully closed, aperture, and how much the aperture should be when aperture is reduced), and outputs a command signal to the proportional solenoid valves 31a, 31b to 35a, 35b.
[0052]
5 to 9 show operating states of the auxiliary valves 91a, 91b; 101a, 101b; 111a, 111b; 131a, 131b; 701a, 701b by the controller 25.
[0053]
5 shows the operation state of the auxiliary valve in the single operation, FIG. 6 shows the operation state of the auxiliary valve in the traveling 2 combination and the traveling 3 combination, and FIG. 7 shows the operation state of the auxiliary valve in the turning 2 combination and the turning 3 combination. 8 shows the operating state of the auxiliary valve in the front 2 combination, and FIG. 9 shows the operating state of the auxiliary valve in the front 3 combination. In the figure, ○ means fully open, × means fully closed, and △ means throttle. () Shows the operation state in the standby state.
[0054]
The throttle (△) of the auxiliary valve is for the combined operation, and the throttle amount is determined according to the operation amount (pilot pressure signal) of the other party directional switching valve.
[0055]
FIG. 10 shows the relationship between the operation amount of the counter direction switching valve and the opening area of the auxiliary valve when the auxiliary valve is throttled (hereinafter referred to as an opening curve). FIG. 10 shows, as an example, an opening curve of the auxiliary valve 101a on the side of the first hydraulic pump 1a for the arm during the combined operation of the boom raising and the arm cloud. The horizontal axis represents the operation amount of the boom direction switching valve 9, and the vertical axis represents the opening area of the boom direction switching valve 9 and the auxiliary valve 101a. When the directional control valves 9 and 10 for the boom and the arm are operated by the pilot pressure signals 92a and 101a for the combined operation of the boom raising and the arm cloud, the opening area of the meter-in throttle of the directional control valve 9 for the boom is switched. It changes from fully closed to fully open as shown by X0 in FIG. On the other hand, at this time, the opening area of the auxiliary valve 101a on the side of the first hydraulic pump 1a for the arm changes from fully open to fully closed as shown by X1 in FIG. 10 according to the operation amount of the directional control valve 9 for boom. I do.
[0056]
The same applies to the opening curves in the throttle operation of the other auxiliary valves during the combined operation.
[0057]
As described above, the auxiliary valves 91a, 91b; 101a, 101b; 111a, 111b; 131a, 131b; 701a, 701b have a backflow prevention function. As described above, the auxiliary valves 91a and 91b; 101a and 101b; 111a and 111b; 131a and 131b; 701a and 701b have a backflow prevention function, and these auxiliary valves are opened and closed (flow cutoff function), and the above-described throttle is provided. By providing the function (variable resistance function), the functions of the merging circuit, load check, and priority circuit can be realized by a circuit using a closed center type valve. This point is described in detail in JP-A-9-79212.
[0058]
FIG. 11 shows details of the bleed valves 81 to 88 and the pump control valves 77 and 78.
[0059]
The first bleed valve 81 is for right running, the second bleed valve 82 is for bucket 1, the third bleed valve 83 is for boom 1, and the fourth bleed valve 84 is for arm 2 and spare 2 The fifth bleed valve 85 is for swivel and spare 2, the sixth bleed valve 86 is for arm 1, the seventh bleed valve 87 is for boom 2 and bucket 2, and the eighth bleed valve 88 Is for left running. Here, for example, “1” of “for bucket 1” means that it operates first (first stage) when the bucket is operated, and “2” of “for bucket 2” is the next (second stage) when the bucket is operated. ), Whereby the discharge oil of the first hydraulic pump 1a is first supplied to the bucket cylinder 5, and then the discharge oil of the second hydraulic pump 1b is supplied to the bucket cylinder 5 in a merged manner. See below). The same applies to “1” and “2” of other actuators.
[0060]
The first to eighth bleed valves 81 to 88 are two-port three-position switching valves having a neutral position in the center of the drawing and left and right operating positions, respectively, and fully open the bleed throttle when in the neutral position in the center of the drawing. The opening area of each bleed stop is reduced from fully open to fully closed as the operation is made to the left and right operation positions and the operation amount increases. The first to eighth bleed valves 81 to 88 are pilot operated valves having hydraulic drive units 81a, 81b to 88a, 88b at both ends of the spool, respectively, and pilot pressure signals 142a, 142b; 112a, 112b; 92a, 92b, respectively. 711a, 711b; 712a, 712b; 102a, 102b; 713a, 112b; 132a, 132b.
[0061]
The pump control valve 77 is a valve that generates a pump control pressure that increases as the flow rate of the pressure oil flowing through the bypass line 25a decreases, and is a throttle 77a provided in the bypass line 25a, a variable relief valve 77b, and a throttle 77a. And a hydraulic drive unit 77d that adjusts the force (relief set pressure) of the spring 77c of the variable relief valve 77b in accordance with the pressure on the upstream side of the hydraulic drive unit 77d. A throttle 77e is provided between the variable relief valve 77b and the pilot hydraulic pressure source 79, and the pressure between the throttle 77e and the variable relief valve 77b is guided as a pump control pressure to the regulator 2a of the hydraulic pump 1a. When the first to fourth bleed valves 81 to 84 are in the fully opened state shown in the drawing, the flow rate flowing through the bypass line 25a becomes maximum, and the pressure upstream of the throttle 77a becomes maximum. With this pressure, the hydraulic drive unit 77d operates to minimize the force of the spring 77c (set relief pressure), and controls the pressure (pump control pressure) between the throttle 77e and the variable relief valve 77b to be the minimum. The regulator 2a is of a positive control type. When the pump control pressure is the lowest, the regulator 2a minimizes the displacement (discharge capacity) of the hydraulic pump 1a and controls the discharge flow rate of the hydraulic pump 1a to a minimum. As any one of the first to fourth bleed valves 81 to 84 is operated and the opening area is reduced, the flow rate flowing through the bypass line 25a decreases, and the pressure upstream of the restriction 77a decreases. Accordingly, the hydraulic drive unit 77d operates to increase the force of the spring 77c (set relief pressure), and increases the pressure (pump control pressure) between the throttle 77e and the variable relief valve 77b. Thus, the regulator 2a controls the hydraulic pump 1a to increase the tilt (discharge capacity) and increase the discharge flow rate of the hydraulic pump 1a.
[0062]
The same applies to the pump control valve 78. The pump control valve 78 includes a throttle 78a, a variable relief valve 78b, and a hydraulic drive unit 78d for adjusting the force (relief set pressure) of a spring 78c of the variable relief valve 78b. The pressure between the valves 78b is guided to the regulator 2b of the hydraulic pump 1b as a pump control pressure.
[0063]
12 and 13 show the relationship between the operation amount of the bleed valve and the opening area of the bleed throttle (hereinafter, referred to as an opening curve).
[0064]
FIG. 12 shows the opening curve of the bleed throttle of the bleed valve in relation to the operation direction of the actuator to which the discharge oils of the first and second hydraulic pumps 1a and 1b are combined and supplied, and as an example, relates to the boom raising direction. FIG. 9 shows an opening curve of a bleed throttle at an operating position on the right side of the bleed valves 83 and 87 in the drawing. The horizontal axis represents the operation amount of the bleed valves 83 and 87, and the vertical axis represents the opening area of the bleed throttle. For comparison, the opening curve of the meter-in stop in the boom raising direction of the boom direction switching valve 9 is also shown. When the boom directional control valve 9 is operated in the boom raising direction by the pilot pressure signal 92a, the opening area of the meter-in throttle of the directional control valve 9 is changed from fully closed to fully open as indicated by X0 in FIG. To change. On the other hand, at this time, the bleed valve 83 on the first hydraulic pump 1a side and the bleed valve 87 on the second hydraulic pump 1b side are also operated to the left by the pilot pressure signal 92a (pilot pressure signal 713a), and the bleed valve 83 The opening area of the bleed throttle at the right operating position in the drawing changes from fully open to fully closed as indicated by X2 in FIG. 12 according to the operation amount, and the opening area of the bleed throttle at the right operating position of the bleed valve 87 in the drawing. Changes from fully open to fully closed as shown by X3 in FIG. 12 in accordance with the amount of operation of the bleed valve 83.
[0065]
When the boom direction switching valve 9 is operated in the boom raising direction in this manner, the bleed valves 83 and 87 are sequentially throttled in conjunction with the operation of the direction switching valve 9 (bleed flow rate control), so that the first The discharge pressure of the hydraulic pump 1a is gradually increased, and the discharge oil of the first hydraulic pump 1a is supplied to the boom cylinder 3, and then the discharge pressure of the second hydraulic pump 1b is gradually increased. The discharge oil 1b is supplied to the boom cylinder 3. The flow characteristics (metering characteristics) at this time depend on the combination of the characteristics of the opening curves of the meter-in throttle of the boom directional control valve 9 and the characteristics of the opening curves of the bleed throttles of the bleed valves 83 and 87 (bleed flow characteristics). By appropriately setting them, metering characteristics according to the load characteristics of the boom cylinder 3 can be obtained, and appropriate flow control can be performed. Further, since the boom cylinder 3 is started while a part of the pressure oil is being extracted by the bleed valves 83 and 87, a cushion effect against the hydraulic pressure fluctuation is obtained, and the boom is gradually increased by gradually increasing the discharge pressure of the hydraulic pumps 1a and 1b. A sudden change in the speed of the cylinder 3 can be prevented.
[0066]
Bleed throttle at the operating position on the right side of the bleed valves 86 and 84 related to the arm cloud, bleed throttle at the operating position on the left side of the bleed valves 86 and 84 related to the arm dump, and right side of the bleed valves 82 and 87 related to the bucket cloud. Bleed throttle at the operation position of, bleed throttle at the operation position on the left side of the bleed valves 82 and 87 related to bucket dump, and bleed throttle at the operation position of the bleed valves 85 and 84 at the right side of the illustration for spare one-way operation. The bleed restrictors in the operation positions on the left side in the drawing of the bleed valves 85 and 84 relating to the opposite direction operation also move in the operation directions of the other actuators to which the discharge oils of the first and second hydraulic pumps 1a and 1b are merged and supplied. Bleed valve related to The opening curves, the schematic is the same. However, the order of the operations is “1” and “2” described above. In addition, the characteristics of the aperture curves of the bleed apertures are delicately changed so that metering characteristics corresponding to the load characteristics in the respective operation directions of the actuator can be obtained.
[0067]
FIG. 13 shows an opening curve of a bleed throttle of a bleed valve related to an operation direction of an actuator to which only one of the first and second hydraulic pumps 1a and 1b is supplied with discharge oil. FIG. 9 shows an opening curve of a bleed throttle at an operating position on the right side in the drawing of the bleed valve 81 in the forward direction. The horizontal axis indicates the operation amount of the bleed valve 81, and the vertical axis indicates the opening area of the bleed throttle. For comparison, the opening curve of the meter-in throttle in the forward direction of the direction switching valve 14 for right traveling is also shown. When the rightward traveling direction switching valve 14 is operated in the forward direction by the pilot pressure signal 142a, the opening area of the meter-in throttle of the direction switching valve 14 is changed from fully closed to fully open as shown by X4 in FIG. To change. On the other hand, at this time, the bleed valve 81 is also operated to the left in the figure by the pilot pressure signal 142a, and the opening area of the bleed throttle at the operating position on the right side of the bleed valve 81 in accordance with the operation amount is as shown by X5 in FIG. Changes from fully open to fully closed.
[0068]
As described above, when the right-direction switching valve 14 is operated in the forward direction, the bleed valve 81 is throttled in conjunction with the operation of the direction switching valve 14 (bleed flow rate control), thereby discharging the first hydraulic pump 1a. The pressure is gradually increased, and the discharge oil of the first hydraulic pump 1 a is supplied to the right traveling motor 8. At this time, the flow characteristic (metering characteristic) depends on the combination of the characteristic of the opening curve of the meter-in throttle of the directional control valve 14 for rightward traveling and the characteristic of the opening curve of the bleed throttle of the bleed valve 81 (bleed flow characteristic). By setting them appropriately, metering characteristics according to the load characteristics of the right traveling motor 8 can be obtained, and appropriate flow control can be performed. Further, since the right running motor 8 is started while a part of the pressure oil is being extracted by the bleed valve 81, a cushion effect against the hydraulic pressure fluctuation is obtained, and the right running motor 8 is gradually increased by increasing the discharge pressure of the hydraulic pump 1a. Can be prevented from suddenly driving.
[0069]
Bleed throttle at the left operating position of bleed valve 81 involved in rightward traveling backward, bleed throttle at the right operating position of bleed valve 88 involved in leftward traveling advancement, and left side of bleed valve 88 involved in leftward traveling backward. The first and second hydraulic pumps also include a bleed restrictor in the operating position of, a bleed restrictor in the operating position on the right side of the bleed valve 85 relating to the turning right, and a bleed restrictor in the operating position on the left side of the bleed valve 85 relating to the turning left in the drawing. This corresponds to the bleed throttle of the bleed valve related to the operation direction of the actuator to which only one of the discharge oils 1a and 1b is supplied, and the outline of the opening curves of these bleed throttles is the same. However, the characteristics of the aperture curves of the bleed apertures are slightly changed so as to obtain metering characteristics according to the load characteristics in the respective operation directions of the actuator.
[0070]
The bleed control for the arm 2 and the spare 2, the swivel and the spare 1, and the boom 2 and the bucket 2 takes into account that the required flow characteristics are similar, and the bleed valves 84, 85, and 87 are The arm 2 is used for the spare 2, the swing and the spare 1 are used, and the boom 2 is used for the bucket 2. Thereby, the number of bleed valves can be reduced as much as possible, and the direction switching valve device can be simplified.
[0071]
As described above, by providing the bleed valves 81 to 88 and controlling them, as described in JP-A-9-79212, auxiliary valves 91a, 91b; 101a, 101b; , 111b; 131a, 131b; 701a, 701b are separated from the bleed circuits formed by the bleed valves 81 to 88, so that the degree of priority and the metering characteristics can be controlled independently.
[0072]
In the hydraulic system described in Japanese Patent Application Laid-Open No. 9-79212, one bleed valve is provided for each of the first and second bypass lines 25a and 25b shown in FIG. The valve is shared by all directional switching valves related to the first hydraulic pump, the bleed valve on the second bypass line 25b side is shared by all directional switching valves related to the second hydraulic pump, and operation of the directional switching valve is performed. At times, by controlling the bleed valves in an electro-hydraulic manner, a function equivalent to the center bypass throttle of each directional control valve in the conventional open center circuit is to be obtained. However, it is extremely difficult to properly operate the bleed valves for all the directional control valves related to one hydraulic pump with one bleed valve and perform appropriate flow control.
[0073]
In the hydraulic system shown in FIG. 1, the first to fourth bleed valves 81 to 84 are provided in the first bypass line 25a as described above, and the fifth to eighth bleed valves 85 to 85 are provided in the second bypass line 25b. 88, and by setting opening curves according to the load characteristics in the respective operating directions of the actuators 1 to 8, 69 as shown in FIGS. Like the center bypass throttle, the bleed flow rate can be individually controlled for all of the directional control valves, so that the flow rate can be controlled in accordance with the load characteristics of the actuator and a cushion effect against hydraulic pressure fluctuation can be obtained.
[0074]
Next, details of the direction switching valve device according to the embodiment of the present invention will be described. The directional switching valve device according to the present embodiment includes directional switching valves 9 to 14, 70, auxiliary valves 91a, 91b; 101a, 101b; 111a, 111b; 131a, 131b; 701a, 701b, a relief valve 75, and a bleed valve 81. To 88, pump control valves 77 and 78, and the like.
[0075]
14 is an exploded view of the left and right side surfaces of the direction switching valve device according to the present embodiment, FIG. 15 is a top view of the direction switching valve device, FIG. 16 is a right side view of the direction switching valve device, FIG. 17 is a left side view of the direction switching valve device. In the following description, “up”, “down”, “right”, “left”, “front”, and “rear” are expressed with reference to the state shown in FIG.
[0076]
The direction switching valve device according to the present embodiment has a substantially rectangular housing 207 having an upper surface 201 and a lower surface 202, a right side surface 203, a left side surface 204, a front end surface 205, and a rear end surface 206.
[0077]
On the upper surface 201 of the housing 207, the first and second pump ports 211a and 211b, the right running actuator ports 212a and 212b, the left running actuator ports 213a and 213b, the turning actuator ports 214a and 214b, and the spare Actuator ports 215a and 215b, bucket actuator ports 216a and 216b, boom actuator ports 217a and 217b, arm actuator ports 218a and 218b, and drain ports 219 and 220. The first and second pump ports 211a and 211b are connected to the first and second hydraulic pumps 1a and 1b by hydraulic piping, respectively, and actuated ports 212a and 212b for right traveling and actuator ports 213a and 213b for left traveling. , Turning actuator ports 214a and 214b, spare actuator ports 215a and 215b, bucket actuator ports 216a and 216b, boom actuator ports 217a and 217b, and arm actuator ports 218a and 218b, respectively. The traveling motor 8, the left traveling motor 7, the turning motor 6, the spare actuator 69, the bucket cylinder 5, the boom cylinder 3, and the arm cylinder 4 are connected by hydraulic piping, and the drain ports 219 and 220 are connected to the tank 29. It is connected by hydraulic piping.
[0078]
A first side block 225 is fixed to the right side surface 203 of the housing 207 by bolts (not shown), and a second side block 226 is fixed to the left side surface 204 by bolts (not shown). The first side block 225 includes pilot ports 231a to 237a for directional control valves, pilot ports 241a to 245a for auxiliary valves, pilot ports 251a to 254a and 251b to 254b for bleed valves, and a pump control port 256a. Similarly, the second side block 226 has pilot ports 231b to 237b for directional control valves, pilot ports 241b to 245b for auxiliary valves, and pilot ports 261a to 264a and 261b to 264b for bleed valves. , A pump control port 256b, and a drain port 221 are provided. The first and second side blocks 225 and 226 are provided with connection plugs 258a and 258b with throttles, and the connection plugs with throttles 258a and 258b are provided with pilot hydraulic power supply ports 257a and 257b.
[0079]
The pilot ports 231a and 231b for the direction switching valves are for right traveling (for the direction switching valve 14), and are connected to the output ports of the operation pedal device 22 for right traveling so that the pilot pressure signals 142a and 142b for right traveling are guided. The pilot ports 232a and 232b are connected to each other by hydraulic piping, and the pilot ports 232a and 232b are for left traveling (for the direction switching valve 13). The output ports of the left traveling operation pedal device 21 are provided so that pilot pressure signals 132a and 132b for left traveling are guided. The pilot ports 233a and 233b are for turning (for the direction switching valve 12), and are connected to the output port of the operating lever device 20 by hydraulic piping so that the pilot pressure signals 122a and 122b for turning are guided. The pilot ports 234a and 234b are reserved (for the direction switching valve 70). The pilot pressure signals 702a and 702b are connected to the output port of the operating lever device 23 by hydraulic piping so that the pilot pressure signals 702a and 702b are guided. The pilot ports 236a and 236b are for booms (for the direction switching valve 10), and pilot pressure signals 92a and 92b for booms are connected to the output ports of the operation lever device 19 so that the pilot ports 112a and 112b are guided. The operation lever device 20 is connected to the output port of the operation lever device 19 by a hydraulic pipe so that the pilot ports 237a and 237b are for the arm (for the direction switching valve 9) and the pilot pressure signals 102a and 102b for the arm are guided. Hydraulic port connected to the output port of To have.
[0080]
Pilot ports 241a and 241b for auxiliary valves are for left running (for auxiliary valves 131a and 131b), are connected to output ports of proportional solenoid valves 34a and 34b by hydraulic piping, and pilot ports 242a and 242b are for auxiliary (auxiliary). The valves 701 and 702) are connected to the output ports of the proportional solenoid valves 35a and 35b by hydraulic piping. The pilot ports 243a and 243b are for buckets (for the auxiliary valves 111a and 111b) and the proportional solenoid valves 33a and 33b. The pilot ports 244a and 244b are for booms (for auxiliary valves 91a and 91b), and the pilot ports 244a and 245b are connected to the output ports of the proportional solenoid valves 31a and 31b by hydraulic piping. Is for the arm (for the auxiliary valves 101a and 101b), Valve 32a, are connected by hydraulic pipes to 32b of the output ports.
[0081]
The pilot ports 251a and 251b for the bleed valve are for right running (for the bleed valve 81), and hydraulic piping is provided to the output port of the operating pedal device 22 for right running so that the pilot pressure signals 142a and 142b for right running are guided. The pilot ports 252a and 252b are for the bucket 1 (for the bleed valve 82), and are connected to the output port of the operation lever device 19 by hydraulic piping so as to guide the pilot pressure signals 112a and 112b for the bucket. The ports 253a and 253b are for the boom 1 (for the bleed valve 83), and are connected to the output port of the operation lever device 19 by hydraulic piping so as to guide the boom pilot pressure signals 92a and 92b, and the pilot ports 254a and 254b are arms. 2 and spare 2 (for bleed valve 84) Yes, the pilot pressure signals 102a, 102b for the arm or the pilot pressure signals 702a, 702b for the spare are connected to the output ports of the shuttle valves 24a, 24b by hydraulic piping so that the pilot ports 261a, 261b are used for the turning and the spare 1. (For the bleed valve 85), and is connected to the output ports of the shuttle valves 24c and 24d by hydraulic piping so that the pilot pressure signals 122a and 122b for turning or the pilot pressure signals 702a and 702b for standby are guided. , 262b are for the arm 1 (for the bleed valve 86), and are connected to the output port of the operating lever device 20 by hydraulic piping so that the arm pilot pressure signals 102a, 102b are guided, and the pilot ports 263a, 263b are connected to the boom 2 and Bucket 2 (for the bleed valve 87), the shuttle valve 24e and the operating lever device 19 so that the pilot pressure signal 112a for bucket cloud or the pilot pressure signal 92a for raising the boom and the pilot pressure signal 112b for bucket dumping are guided. The pilot ports 264a and 264b are connected to the output port by hydraulic piping, and the pilot ports 264a and 264b are for left running (for the bleed valve 88). It is connected to the output port by hydraulic piping.
[0082]
The pump control ports 256a, 256b are connected to the regulators 2a, 2b of the hydraulic pumps 1a, 1b by hydraulic piping, and the pilot hydraulic source ports 257a, 257b of the connection plugs with throttle 258a, 258b are connected to the pilot hydraulic source 79 by hydraulic piping. , The drain port 221 is connected to the tank 29 by hydraulic piping.
[0083]
18 to 26 are AA line, BB line, CC line, DD line, EE line, FF line, GG line, and FIGS. 16 and 17, respectively. It is each sectional view of the HH line and the II line.
[0084]
18 to 26, in a housing 207, first and second two pump passages 301 and 302 (corresponding to the first and second pump lines 30a and 30b) are parallel to each other at substantially the same height. The first and second two tank passages 303, 304 are formed at a height position above and separated from the first and second pump passages 301, 302. They are formed at the same height so as to extend in the front-rear direction side by side in parallel with each other.
[0085]
As shown in FIG. 18, the first and second pump passages 301 and 302 communicate with the first and second pump ports 211a and 211b at their front ends via passages 305 and 306, respectively. The passages 307 and 308 branch off from the passages 305 and 306, and these passages 307 and 308 are further connected to one passage 309. The flow of the pressure oil from the passages 305 and 306 to the passage 309 is formed in the passages 307 and 308. Check valves 73a and 73b are provided. The main relief valve 75 is mounted on the passage 309, and the discharge side of the main relief valve 75 communicates with the first tank passage 303 via the passage 310.
[0086]
As shown in FIG. 26, the first and second tank passages 303 and 304 are connected to each other by a cavity 312 at the rear end portion, and the first tank passage 303 is connected to the drain passage 221 and the second tank passage 304 is provided. Communicates with the drain port 219 via the passage 313.
[0087]
As shown in FIGS. 19 to 25, spool bores 321, 322, 323, 324, 325, 326, and 327 for the directional control valve are provided in the housing 207, and the first and second tank ports 303 and 304 are provided. Are formed in parallel at a predetermined interval from each other.
[0088]
A directional switching valve spool 331 constituting the right traveling directional switching valve 14 is slidably inserted into the spool bore 321 shown in FIG. 19, and the left traveling directional switching valve 13 is inserted into the spool bore 322 shown in FIG. The directional control valve spool 332 constituting the turning directional control valve 12 is slidably inserted into the spool bore 323 shown in FIG. The directional control valve spool 334 constituting the spare directional control valve 70 is slidably inserted into the spool bore 324 shown in FIG. 23, and the spool bore 325 shown in FIG. A switching valve spool 335 is slidably inserted, and a direction switching valve spool 336 constituting the boom direction switching valve 9 is slidably inserted into a spool bore 326 shown in FIG. Is inserted into, the directional control valve spool 337 constituting the directional control valve 10 for the arm is inserted slidably in a spool bore 327 shown in FIG. 25.
[0089]
The spool bores 321, 322, 323, 324, 325, 326, and 327 for the directional control valves and the directional control valve spools 331 to 337 are located at a height position separated from the first and second pump passages 301 and 302. The first and second pump passages 301 and 302 are arranged side by side in parallel with each other in a direction crossing the first and second pump passages 301 and 302.
[0090]
Annular pump ports 341 to 347 are formed in the center of the spool bores 321 to 327, respectively, and annular actuator ports 351a, 351b to 357a, 357b are formed on both sides thereof. The pump port 341 in FIG. 19 is connected to the first pump passage 301 via feeder passages 361 and 371 (corresponding to the traveling feeder line 143a), and the pump port 342 in FIG. 20 is connected to the feeder passage 362 and the feeder passages 372a and 372b. (Equivalent to the first and second traveling feeder lines 133a and 133b) and can be connected to the first and second pump passages 301 and 302, and the pump port 343 shown in FIG. The pump port 344 in FIG. 22 is connected to the feeder passage 364 and the feeder passages 374a and 374b (the first and second spare feeders). (Corresponding to the lines 703a and 703b) and the first and second pump passages 301 and 3 The pump ports 345, 346, and 347 of FIGS. 23, 24, and 25 are also connected to the feeder passage 365 and the feeder passages 375a and 375b (the first and second bucket feeder lines 113a and 113b, respectively). ), Feeder passage 366 and feeder passages 376a and 376b (corresponding to first and second arm feeder lines 103a and 103b), and feeder passage 367 and feeder passages 377a and 377b (first and second boom feeders). (Corresponding to the lines 93a, 93b) to the first and second pump passages 301, 302. Actuator ports 351a, 351b to 357a, 357b are actuator ports 212a, 212b for right traveling opening on housing upper surface 201, actuator ports 213a, 213b for left traveling, actuator ports 214a, 214b for turning, and a spare port, respectively. Actuator ports 215a and 215b, bucket actuator ports 216a and 216b, boom actuator ports 217a and 217b, and arm actuator ports 218a and 218b via passages 381a, 381b to 387a and 387b.
[0091]
The direction switching valve spools 331 to 337 are formed with inflow side notches 391a, 391b to 397a, 397b and outflow side notches 401a, 401b to 407a, 407b, respectively. The inflow side notches 391a and 391b in FIG. 19 form a meter-in variable throttle that connects the pump port 341 to the actuator ports 351a and 351b according to the moving direction of the direction switching valve spool 331, and the outflow side notches 401a and 401b A meter-out variable restrictor for connecting the actuator ports 351a, 351b to the tank passages 303, 304 in accordance with the moving direction of the direction switching valve spool 331 is formed. Similarly, the inflow side notches 392a, 392b to 397a, and 397b in FIGS. 20 to 25 are connected to the pump ports 342 to 347 according to the moving direction of the directional control valve spools 332 to 337, respectively. Are formed, and the outlet notches 402a, 402b to 407a, 407b are also connected to the actuator ports 352a, 352b to 357a, 357b in accordance with the moving direction of the directional control valve spools 332 to 337, respectively. A meter-out variable diaphragm communicating with 303 and 304 is formed.
[0092]
The spool bores 321 to 327 are opened on the left and right side surfaces 203 and 204 of the housing 207, and spring chambers and pressure receiving chambers 411 a to 417 a are formed at corresponding locations of the first side block 225, and corresponding to the second side block 226. Pressure receiving chambers 411b to 417b are formed at the locations, the spring chambers and pressure receiving chambers 411a to 417a communicate with pilot ports 231a to 237a, and the pressure receiving chambers 411b to 417b communicate with pilot ports 231b to 237b. Further, spring mechanisms 421 to 427 for holding the directional control valve spools 331 to 337 at the neutral position are disposed in the spring / pressure receiving chambers 411a to 417a.
[0093]
In FIG. 20, valve bores 432a and 432b are provided in the housing 207 in parallel with the spool bore 322 for the directional control valve so as to be aligned with the feeder passages 372a and 372b and open to the first and second pump passages 301 and 302. The poppet valves 442a and 442b of the left traveling auxiliary valves 131a and 131b are formed and formed in the valve bores 432a and 432b. Small spool bores 452a, 452b are formed below the poppet valves 442a, 442b in parallel with the valve bores 432a, 432b so as to be aligned with each other, and the small spool bores 452a, 452b are provided with the left traveling auxiliary valves 131a, 131b. Pilot spools 462a and 462b are inserted.
[0094]
FIG. 27 is an enlarged view of the poppet valve 442a and the pilot spool 462a of the left traveling auxiliary valve 131a.
[0095]
The poppet valve 442a of the traveling auxiliary valve 131a is slidably inserted into the opening of the feeder passage 372a to the pump passage 301 and the opening of the valve bore 432a to the pump passage 301 as shown in an enlarged manner in FIG. An opening 503a for controlling a flow rate that changes an opening area from the pump passage 301 to the feeder passage 372a in accordance with a movement stroke of the poppet 501a is provided at a portion where the poppet 501a is inserted into the feeder passage 372a. The back pressure chamber 505a is formed on the opposite side of the poppet 501a. A spring 506a for holding the poppet 501 at the closed position is disposed in the back pressure chamber 505a. The poppet 501a has a pressure receiving portion 507a that receives the pressure of the feeder passage 372a, a pressure receiving portion 509a that receives the pressure of the pump passage 301, and a pressure receiving portion 511a that receives the pressure of the back pressure chamber 505a. Assuming that the pressure receiving area is Ap, the effective pressure receiving area of the pressure receiving section 509a is Az, and the effective pressure receiving area of the pressure receiving section 511a is Ac, the relationship Ac = Az + Ap is established. Further, a feedback slit 513a that changes an opening area to the back pressure chamber 505a in accordance with a movement stroke of the poppet 501a is formed in a portion where the poppet 501a is inserted into the valve bore 432a. The poppet 501a has an internal passage 515a for connecting the pump passage 301 to the feedback slit 513a. The internal passage 515a has a load check valve 517a for preventing backflow of pressure oil from the feedback slit 513a to the pump passage 301. Is provided.
[0096]
A notch 522a is formed in the pilot spool 462a, and the notch 522a forms a pilot variable throttle that changes an opening area according to a movement stroke of the pilot spool 462a. In the housing 207, a passage 532a connecting the back pressure chamber 505a to the entry side of the notch 522a of the small spool bore 452a, and a passage 542a connecting the exit side of the notch 522a of the small spool bore 452a to the feeder passage 372a. Is formed, and by changing the opening area of the notch 522a (pilot variable throttle), the pilot flow rate flowing through the pilot line constituted by the internal passage 515a, the feedback slit 513a, the back pressure chamber 505a, and the passages 532a and 542a of the poppet 501. Changes.
[0097]
One end of the pilot spool 462a projects into a spring chamber / pressure receiving chamber 552a formed in the first side block 225, and the spring chamber / pressure receiving chamber 552a communicates with the pilot port 241a, and the output pressure of the proportional solenoid valve 34a from the pilot port 241a. , And the pilot spool 462a is moved according to the pressure. A spring mechanism 553a that holds the pilot spool 462a at a neutral position is disposed in the spring / pressure receiving chamber 552a.
[0098]
The operating principle of the poppet type auxiliary valve 131a configured as described above is known, and the effective pressure receiving area Ac of the pressure receiving section 511a on the back pressure chamber 505a side of the poppet 501a and the effective pressure receiving area of the pressure receiving section 509a on the pump passage 301 side. Assuming that the ratio to Ap is K, the pressure in the pump passage 301 (pump pressure) is Pp, and the pressure in the feeder passage 372a (pressure on the inlet side of the meter-in variable throttle) is Pz, the pressure Pc in the back pressure chamber 505a is K, The poppet 501a moves so that it becomes a function of Pp and Pz, and the opening area formed by the feedback slit 513a has a predetermined relationship determined by K with the opening area formed by the notch 522a of the pilot spool 462a. For example, if Ac: Ap = 2: 1 and K = 1/2, Pc = (Pp + Pz) / 2, so that the opening area formed by the feedback slit 513a is equal to the opening area formed by the notch 522a of the pilot spool 462a. The poppet 501a moves. At this time, if the size of the opening 503a is properly selected, the opening area from the pump passage 301 to the feeder passage 372a can be freely controlled by moving the pilot spool 462a. Since the pilot spool 462a is controlled by the proportional solenoid valve 34a, the opening area from the pump passage 301 to the feeder passage 372a can be controlled by the controller 25 (variable resistance function).
[0099]
When a pressure higher than that of the pump passage 301 is applied to the feeder passage 372a, pressure is applied to the pressure receiving portion 507a of the poppet 501 on the feeder passage 372a side, and at the same time, the passage 542a, the small spool bore 452a, the notch 522a, and the passage 532a. The same pressure acts on the pressure receiving portion 511a of the poppet 501 on the side of the back pressure chamber 505a. Here, the pressure receiving portion 511a of the poppet 501 has a larger effective pressure receiving area than the pressure receiving portion 507a. Therefore, the poppet 501 is pressed toward the feeder passage 372a, and the poppet 501 functions as a load check valve (backflow prevention function).
[0100]
The poppet valve 442b and the pilot spool 462b of the left traveling auxiliary valve 131b have the same configuration, and the same portions as those relating to the poppet valve 442a and the pilot spool 462a are denoted by the same reference numerals with the suffix b added thereto. The inner ends of the small spool bores 452a, 452b communicate with a drain passage 531.
[0101]
22, 23, 24, and 25, a directional control valve is provided in the housing 207 so as to be aligned with the feeder passages 374 a, 374 b to 377 a, 377 b and open to the first and second pump passages 301, 302. Valve bores 434a, 434b to 437a, 437b are formed in parallel with the spool bores 324 to 327 for use, and poppet valves 444a, 444b of auxiliary auxiliary valves 701a, 701b and auxiliary valves for buckets are provided in the valve bores 434a, 434b to 437a, 437b. Poppet valves 445a and 445b for 111a and 111b, poppet valves 446a and 446b for boom auxiliary valves 91a and 91b, and poppet valves 447a and 447b for arm auxiliary valves 101a and 101b are arranged. Also, small spool bores 454a, 454b to 457a, 457b are formed below the poppet valves 444a, 444b to 447a, 447b in parallel with the valve bores 434a, 434b to 437a, 437b so as to align with each other. Pilot spools 464a and 464b of auxiliary auxiliary valves 701a and 701b, pilot spools 465a and 465b of auxiliary valves 111a and 111b for buckets, pilot spools 466a and 466b of auxiliary valves 91a and 91b for booms, and arms 454b to 457a and 457b. The pilot spools 467a and 467b of the auxiliary valves 101a and 101b are inserted.
[0102]
Poppet valves 444a and 444b of spare auxiliary valves 701a and 701b and pilot spools 464a and 464b, poppet valves 445a and 445b of bucket auxiliary valves 111a and 111b, and pilot spools 465a and 465b, and poppet valves of boom auxiliary valves 91a and 91b. 446a, 446b and the pilot spools 466a, 466b, the poppet valves 447a, 447b of the arm auxiliary valves 101a, 101b and the pilot spools 467a, 467b are also provided, and the poppet valves 442a, 442b and the pilot spool 462a of the left traveling auxiliary valves 131a, 131b. Notches 524a, 534b to 527a, 527b are formed in pilot spools 464a, 464b to 467a, 467b, and passages are formed in housing 207. 34a, 534b~537a, 537b, passages 544a, 544b~547a, 547b are formed, the first and second side blocks 225 and 226 the spring chamber and the pressure receiving chamber 554a, 554B～557a, are 557b are formed.
[0103]
However, the opening 503b for controlling the flow rate formed in the poppet 501b of the bucket auxiliary valve 111b shown in FIG. 23 has a small opening area and is configured to function as the fixed throttle 17 (see FIG. 1). .
[0104]
In FIG. 21, a check valve 16 that allows the flow of pressure oil from the pump passage 302 to the feeder passage 373 is disposed at an opening of the feeder passage 373 to the second pump passage 302.
[0105]
In FIG. 22, bores 560a, 560b opening to the passages 384a, 384b of the actuator ports 215a, 215b and passages 561a, 561b connecting the bores 560a, 560b to the tank ports 303, 304 are formed in the housing 207. Closing plugs 562a, 562b are mounted on 560a, 560b. If necessary, a spare overload relief valve may be mounted instead of the closing plug. In FIG. 23, bores 563a and 563b opening to the passages 385a and 385b of the actuator ports 216a and 216b, and passages 564a and 564b connecting the bores 563a and 563b to the tank ports 303 and 304 are formed, and are formed in the bores 563a and 563b. Bucket overload relief valves 565a and 565b are mounted.
[0106]
In FIG. 24, a bore 571 that opens into a passage 386a of an actuator port 217a is formed in a housing 207, a bore 572 that matches the bore 571 is formed in a first side block 225, and anti-drift is formed in these bores 571 and 572. A valve (non-leak valve) 573 is mounted. Further, a bore 574 opening to the passage 386b of the actuator port 217b and a passage 575 connecting the bore 574 to the tank port 304 are formed in the housing 207, and an overload relief valve 576b for a boom is mounted in the bore 574. ing. Further, a passage 577 branched from the vicinity of the actuator port 217a of the passage 386a and a passage 577 in the cross section shown in FIG. 24 are provided in the housing 207 in the front-rear direction from the cross section shown in FIG. 24 to the cross section shown in FIG. 26, a passage 579 that communicates with the drain port 219 in the cross-sectional portion shown in FIG. 26, and a bore 580 that opens into the passage 579 and opens the passage 578, and another bore for the boom is formed in the bore 580. An overload relief valve 576a is mounted.
[0107]
In FIG. 25, similarly, a bore 591 is formed in the housing 207 so as to open to the passage 387a of the actuator port 218a, and a bore 592 is formed in the first side block 225 so as to be aligned with the bore 579. An anti-drift valve (non-leak valve) 593 is mounted. A bore 594 opening to the passage 387b of the actuator port 218b and a passage 595 connecting the bore 594 to the tank port 304 are formed in the housing 207. The bore 594 is provided with an overload relief valve 596b for a boom. ing. Further, in the housing 207, a passage 598 extending in the front-rear direction from the anti-drift valve portion of the passage 387a of the actuator port 218a to the cross-sectional portion shown in FIG. 26, and a passage 598 which opens to the passage 579 in the cross-sectional portion shown in FIG. An open bore 599 is formed, and another overload relief valve 596a for a boom is mounted in the bore 599.
[0108]
FIG. 28 shows details of the anti-drift valve 573 relating to the boom direction switching valve 9.
[0109]
28, an anti-drift valve 573 includes a poppet valve 610 that opens and closes a passage 386a, a spring receiver 612 that holds a spring 611 that biases the poppet valve 610 in a valve closing direction, and a sleeve 613 to which the spring receiver 612 is fixed. A back pressure chamber 614 is formed between the poppet valve 610 and the spring receiver 612, and a drain chamber 615 is formed between the spring receiver 612 and the sleeve 613. Further, a piston valve 618 in which a pilot valve 616 and a pilot piston 617 are integrated is slidably inserted into the sleeve 613, and a control chamber 619 is formed between the pilot valve 616 and the pilot piston 617. A pilot chamber 620 is formed on the back. The control chamber 619 communicates with the pilot port 217a side of the passage 386a through the passage 621 formed in the sleeve 613 and the passages 622 and 623 formed in the housing 207 and the first side block 225, and is formed in the sleeve 613. It communicates with the back pressure chamber 614 via the passage 624 and the outer peripheral groove 625. A throttle 626 is provided in the passage 621. A drain passage 627 is formed in the first side block 225, and the drain chamber 615 communicates with the drain passage 627 through a passage 628 formed in the sleeve 613 and a gap 629 on the rear end side of the sleeve 613. . The drain passage 627 passes through the outer peripheral groove 630 of the pilot port 236a, further connects to the drain passage 631 shown in FIG. 15, and reaches the drain port 632.
[0110]
Returning to FIG. 28, the pilot chamber 620 communicates with the spring chamber and pressure receiving chamber 416a of the directional control valve 9 via a path 635 formed in the sleeve 613 and a path 636 formed in the first side block 225, and The pilot pressure signal 92a for raising the boom guided to the chamber 416a is also guided to the pilot chamber 620.
[0111]
When the directional control valve spool 336 is at the neutral position shown in FIG. 24, the pilot chamber 620 is almost at the tank pressure, the pilot valve 616 is at the position shown, and the control chamber 619 and the drain chamber 615 are closed. . When the bottom side of the boom cylinder 3 holds a load, the load pressure of the boom cylinder 3 (load holding pressure) is guided to the control chamber 619 via the pilot port 217a, the passages 622, 623, and the passage 621, Furthermore, the poppet valve 610 is guided to the back pressure chamber 614 through the passage 624 and the outer peripheral groove 625, and presses and holds the poppet valve 610 at the valve closing position. Therefore, the pressure oil on the bottom side of the boom cylinder 3 does not leak to the downstream side of the poppet valve 610 in the passage 386a, and the load of the boom cylinder 3 is maintained.
[0112]
When the pilot pressure signal 92a is guided to the spring / pressure receiving chamber 416a of the direction switching valve 9 for raising the boom, the direction switching valve spool 336 is operated to the left in the drawing, and the pilot pressure signal 92a is transmitted to the pilot chamber 620. Then, the pilot valve 616 is pushed to the left in the figure to make the control chamber 619 communicate with the drain chamber 615. Therefore, the pressure in the control chamber 619 decreases to near the tank pressure, and the reduced pressure is guided to the back pressure chamber 614 via the passage 624 and the outer circumferential groove 625. As a result, the poppet valve 610 is opened by the load pressure acting on the pressure receiving portion 637 of the poppet valve 610, and the pressure oil on the bottom side of the boom cylinder 3 can be discharged.
[0113]
When the pilot pressure signal 92b is led to the spring / pressure receiving chamber 416b of the direction switching valve 9 for raising the boom, the poppet valve 610 is opened by the supply pressure led to the passage 386a, and the pressure is applied to the bottom side of the boom cylinder 3. It becomes possible to supply oil.
[0114]
The structure and operation of the anti-drift valve (non-leak valve) 593 related to the arm direction switching valve 10 are the same as those of the anti-drift valve 573 related to the boom direction switching valve 9.
[0115]
FIG. 29 is a sectional view taken along the line KK of FIGS. 16 and 17.
[0116]
In FIG. 29, in a housing 207, first and second bypass passages 801 and 802 (corresponding to the first and second bypass lines 25a and 25b) are arranged in parallel at substantially the same height and in the front-rear direction. It is formed so as to extend. The first bypass passage 801 is configured by sequentially connecting the bridge passages 651 to 654 and the single downstream passage 655, and the second bypass passage 802 is sequentially connected to the bridge passages 661 to 664 and the downstream single passage 665. Connected and configured. As can be seen from FIGS. 19 and 20, the first and second bypass passages 801 and 802 are on the opposite sides of the first and second pump passages 301 and 302 with the directional control valve spools 331 to 337 therebetween. Are located between the directional control valve spools 331 to 337 and the actuator ports 212a, 212b to 218a, 218b opened on the upper surface 201 of the housing 207.
[0117]
In the housing 207, a spool bore 681-684 and a valve bore 685 are formed parallel to each other at a predetermined interval on the first bypass passage 801 side, and the spool bores 691-694 are formed on the second bypass passage 802 side. And a valve bore 695 are formed in parallel at a predetermined distance from each other, and bleed valve spools 811 to 814 constituting the first to fourth bleed valves 81 to 84 are slidably inserted into the spool bores 681 to 684, Bleed valve spools 821 to 824 constituting fifth to eighth bleed valves 85 to 88 are slidably inserted into the spool bores 691 to 694, and the valve body 815 of the pump control valve 77 slides into the valve bore 685. The valve body 825 of the pump control valve 78 is slidably inserted into the valve bore 695. It is. The bleed valve spools 811 to 814 and the valve body 815 are arranged side by side in the direction crossing the first bypass passage 801, and the bleed valve spools 821 to 824 and the valve body 825 are arranged side by side in the direction crossing the second bypass passage 802. Have been.
[0118]
As described later, the bleed valve spools 811 to 814 and bleed valve spools 821 to 824 include a direction switching valve spool 331 for right traveling, a direction switching valve spool 332 for left traveling, and a direction switching valve spool 333 for turning. On the upper side, the positions are shifted with respect to the directional control valve spools 331, 332, and 333, and the directional control valve spools 331, 332, and 333 are arranged substantially in a staggered manner. Due to the reduced directional distance, the various valve elements are rationally arranged within the limited volume of the housing 202, even with a large number of bleed valve spools, making the entire valve device compact.
[0119]
The uppermost bridge passage 651 of the bridge passages 651 to 654 communicates with the passage 305 communicating with the first pump passage 301 via the passage 671 at the upstream portion as shown in FIG. The upstream-most bridge passage 661 also communicates with a passage 306 that communicates with the second pump passage 302 via a passage 672 at an upstream portion thereof. The most downstream single passages 655, 665 communicate with the pump passages 77, 78 at their downstream portions, respectively, and the tank passages 303, 304 via passages 673, 674 as shown in FIG. ing.
[0120]
Two input ports and one output port forming part of the bridge passages 651 to 654 and the bridge passages 661 to 664 are formed at the center and both sides of the spool bores 681 to 684 and the spool bores 691 to 694, respectively. ing. The valve bores 685 and 695 are formed with annular input ports and output ports forming part of the single passages 655 and 665 and the passages 673 and 674 (see FIG. 21), respectively.
[0121]
Notches 831a, 831b to 834a, 834b are formed in the bleed valve spools 811 to 814 at positions corresponding to the two input ports, and these notches are provided in the upstream bridge passage according to the moving direction of the bleed valve spools 811 to 814. And a bleed restrictor for communicating the downstream bridge passage with the bleed valve spools 821 to 824. Similarly, notches 841a, 841b to 844a and 844b are formed at positions corresponding to the two input ports. Forms a bleed throttle that allows communication between the upstream bridge passage and the downstream bridge passage in accordance with the direction of movement of the bleed valve spools 821 to 824.
[0122]
The spool bores 681 to 684 and the spool bores 691 to 694 open to the left and right side surfaces 203 and 204 of the housing 207, respectively, and spring and pressure receiving chambers 851a to 854a are formed at corresponding locations of the first side block 225. Also, spring chamber / pressure receiving chambers 861a to 864a are formed at corresponding locations of the second side block 226, and the spring chamber / pressure receiving chambers 851a to 854a communicate with the pilot ports 251a to 254a, and the spring chamber / pressure receiving chambers 861a to 864a are formed. Communicates with pilot ports 261a-264a. Further, spring mechanisms 871 to 878 for holding the bleed valve spools 811 to 814 and 821 to 824 at neutral positions are disposed in the spring / pressure receiving chambers 851a to 854a and 861a to 864a.
[0123]
Pressure receiving chambers 851b to 854b and 861b to 864b are formed on the inner end sides of the spool bores 681 to 684 and the spool bores 691 to 694, and these pressure receiving chambers 851b to 854b and 861b to 864b are respectively shown in FIGS. As shown, in the housing 207 and the first and second side blocks 225 and 226, the spool bores 681 to 684 and 691 to 694 and the spring chambers and pressure receiving chambers 851a to 854a and 861a to 864a are formed in parallel. Pilot ports 251b to 254b and pilot ports 261b to 264b are connected via passages 881a, 881b to 888a, 888b (passages 883a, 883b and 887a, 887b are not shown).
[0124]
For example, when the directional control valve spool 336 (see FIG. 24) of the directional control valve 9 for the boom is operated to the left in the boom raising direction by the pilot pressure signal 92a, a notch 396 (meter-in throttle) of the directional control valve spool 336 is provided. The opening area changes from fully closed to fully open as indicated by X0 in FIG. 12 according to the operation amount. On the other hand, at this time, the bleed valve 83 on the first hydraulic pump 1a side is operated to the left in FIG. 29 by the pilot pressure signal 92a (pilot pressure signal 713a), and the second hydraulic pump 1b side is operated. The bleed valve spool 823 of the bleed valve 87 is operated to the right in the drawing of FIG. 29, and the opening area of the notch 833a (bleed throttle) of the bleed valve spool 813 is changed from the fully opened state as indicated by X2 in FIG. The opening area of the notch 843a (bleed throttle) of the bleed valve spool 823 is delayed from that of the bleed valve spool 813 and changes from fully open to fully closed as shown by X3 in FIG. I do. Thereby, as described above, the discharge pressures of the first and second hydraulic pumps 1a and 1b are sequentially increased, and the characteristics of the opening curve of the notch 396 of the boom direction switching valve spool 336 and the notches 833a of the bleed valve spools 813 and 823 are provided. , 843a, the discharge oil of the first and second hydraulic pumps 1a, 1b is supplied to the boom cylinder 3 with flow characteristics (metering characteristics) corresponding to a combination of the characteristics of the opening curves (bleed flow characteristics). At this time, by appropriately setting those characteristics, metering characteristics according to the load characteristics of the boom cylinder 3 can be obtained, and appropriate flow control can be performed. Further, since the boom cylinder 3 is started while a part of the pressure oil is being extracted by the spools 823 and 823 of the bleed valves 83 and 87, a cushioning effect against the hydraulic pressure fluctuation is obtained, and the discharge pressure of the hydraulic pumps 1a and 1b is gradually reduced. , The sudden drive of the boom cylinder 3 can be prevented.
[0125]
The same applies to the bleed valve spools related to the operation directions of the other actuators to which the discharge oils of the first and second hydraulic pumps 1a and 1b are merged and supplied, and the notches (bleed throttles) of the bleed valve spools are opened. The characteristics of the curve are slightly changed so as to obtain metering characteristics according to the load characteristics in the respective operation directions of the actuator.
[0126]
For example, when the directional control valve spool 331 (see FIG. 19) of the directional control valve 14 for right running is operated to the left in the forward direction by the pilot pressure signal 142a, the notch 391b (the meter-in throttle) of the directional control valve spool 331 is operated. 13) changes from fully closed to fully open as indicated by X4 in FIG. 13 according to the amount of operation. On the other hand, at this time, the bleed valve spool 811 of the bleed valve 81 is also operated to the left in FIG. 29 by the pilot pressure signal 142a, and the opening area of the notch 831a (bleed throttle) of the bleed valve spool 811 depends on the operation amount. The state changes from fully open to fully closed as indicated by X5 in FIG. Thereby, as described above, the discharge pressure of the first hydraulic pump 1a is gradually increased, and the characteristics of the opening curve of the notch 391b of the direction switching valve spool 331 for right running and the characteristics of the opening curve of the notch 831a of the bleed valve spool 811 are obtained. The discharge oil of the first hydraulic pump 1a is supplied to the right traveling motor 8 with flow characteristics (metering characteristics) corresponding to the combination of (bleed flow characteristics). At this time, by appropriately setting those characteristics, metering characteristics according to the load characteristics of the right traveling motor 8 can be obtained, and appropriate flow control can be performed. In addition, since the right running motor 8 is started while a part of the pressure oil is being extracted by the spool 811 of the bleed valve 81, a cushion effect against the hydraulic pressure fluctuation is obtained, and the rightward pressure is gradually increased by gradually increasing the discharge pressure of the hydraulic pump 1a. Abrupt driving of the traveling motor 8 can be prevented.
[0127]
The same applies to the bleed valve spools related to the operation directions of the other actuators to which only one of the first and second hydraulic pumps 1a and 1b is supplied with the discharge oil, and the notches (bleed throttles) of the bleed valve spools are opened. The characteristics of the curve are slightly changed so as to obtain metering characteristics according to the load characteristics in the respective operation directions of the actuator.
[0128]
Also, the positional relationship between pilot ports 231a to 233a and pilot ports 251a to 254a and 251b to 254b shown in FIG. 16 and the positional relationship between pilot ports 231b to 233b and pilot ports 261a to 264a and 261b to 264b shown in FIG. As described above, the bleed valve spools 811 to 814 and the bleed valve spools 821 to 824 are located above the direction switching valve spool 331 for right traveling, the direction switching valve spool 332 for left traveling, and the direction switching valve spool 333 for turning. The position is shifted in the front-rear direction with respect to the switching valve spools 331, 332, 333, and is disposed substantially staggered with respect to the direction switching valve spools 331, 332, 333, whereby the height direction of the directional switching valve spool and the bleed valve spool is increased. The distance of , Even bleed valve spool number can be rationally arranged without interfering with various valve element in the volume with limited housing 202, it can be the entire valve apparatus compact.
[0129]
FIG. 30 is an enlarged view of the pump control valve 77. In FIG. 30, an annular input port forming part of the single passage 655 is indicated by reference numeral 655a, and an annular output port forming part of the single passage 673 is indicated by reference numeral 673a.
[0130]
The pump control valve 77 has the above-described valve body 815, and the valve body 815 is formed with a notch 891 constituting the throttle 77. The pump control valve 77 has a sleeve 892 mounted on the first side block 225, and a valve body 894 of a relief valve 77b disposed in a valve bore 893 opening at an end of the sleeve 892 on the housing 207 side. In addition, a valve chamber 895 is formed on the distal end side of the valve body 894 of the relief valve 77b in the valve bore 893.
[0131]
The first side block 225 is provided with a connection port 896 for the connection plug 258a described above, and the connection port 896 communicates with the pump control port 256a through passages 897a, 897b, 897c, and the pilot port of the connection plug 258a for throttle. The hydraulic pressure source port 257a communicates with the passages 897a, 897b, 897c via a throttle 77e formed in the connection plug with throttle 258a.
[0132]
The sleeve 892 is formed with an annular outer peripheral recess 898 communicating with the passage 895b, a passage 899 opening to the outer recess 898, and a passage 900 communicating with the passage 899 and opening to the valve chamber 895. Reference numeral 895 denotes a passage 901 and a spring chamber 902 formed in the valve 894 of the relief valve body 77b, a spring chamber 903 formed in the valve body 815, a shaft passage 904, a spring chamber 905 formed in the housing 207, passages 906 and 907. To the drain port 220 via
[0133]
A spring 910 for urging the valve body 815 in the closing direction of the notch 891 (throttle 77a) is arranged in the spring chamber 905, and a spring 77c of the relief valve 77b is arranged in the spring chambers 902 and 903. The valve body 815 adjusts the set pressure of the spring 77c, that is, the relief valve 77b by being urged leftward in the figure by the pressure oil guided from the input port 655a, and constitutes the hydraulic drive unit 77d described above.
[0134]
When the first to fourth bleed valves 81 to 84 are in the fully open state, the flow rate flowing through the bypass passage 801 becomes maximum, and the pressure upstream of the notch 891 (throttle 77a) becomes maximum. With this pressure, the valve body 815 (the hydraulic drive unit 77d) moves to the left in the figure so as to minimize the force of the spring 77c (set relief pressure). For this reason, the pressure of the pilot hydraulic power source 79 (see FIG. 11) guided from the pilot hydraulic power source port 257a to the passages 897a to 897c via the throttle 77e is such that the pressure oil in the passages 897a to 897c is The fluid flows out from the drain port 220 to the tank via the valve chamber 895, the passage 901 and the valve chamber 902 of the valve body 894, the spring chamber 903 and the shaft passage 904 of the valve body 815, the spring chamber 905 of the housing 207, and the passages 906 and 907. As a result, the pressure is controlled to decrease to the minimum pressure which is the set pressure of the variable relief valve 77b. As one of the first to fourth bleed valves 81 to 84 is operated and the notch of the bleed throttle is narrowed, the flow rate flowing downstream of the bypass passage 801 decreases, and the pressure upstream of the notch 891 (throttle 77a) is reduced. Drops. Accordingly, the valve body 815 (the hydraulic drive unit 77d) moves to the right in the figure by the force of the spring 910 so as to increase the force of the spring 77c (set relief pressure). Therefore, the pressure in the passages 897a to 897c increases with an increase in the force of the spring 77c (set relief pressure). Thus, the regulator 2a controls the hydraulic pump 1a to increase the tilt (discharge capacity) and increase the discharge flow rate of the hydraulic pump 1a.
[0135]
The pump control valve 78 is similarly configured.
[0136]
According to the present embodiment configured as described above, by providing the bleed valves 81 to 88 (bleed valve spools 811 to 814 and 821 to 824) and controlling these, the bleed valves described in JP-A-9-79212 are disclosed. As compared with the conventional open center circuit, the priority circuits formed by the auxiliary valves 91a, 91b; 101a, 101b; 111a, 111b; 131a, 131b; 701a, 701b and the bleed circuits formed by the bleed valves 81-88. It is separated and the priority and the metering characteristics can be controlled independently.
[0137]
Further, first to fourth bleed valves 81 to 84 (bleed valve spools 811 to 814) are provided in the first bypass line 25a (first bypass passage 801), and the second bypass line 25b (second bypass) is provided. The passage 802) is provided with fifth to eighth bleed valves 85 to 88 (bleed valve spools 821 to 824), and as shown in FIGS. 12 and 13, loads in the respective operation directions of the actuators 1 to 8 and 69 are provided. By setting the opening curve according to the characteristics, the bleed flow rate can be controlled individually for all of the directional control valves, similar to the center bypass throttle of each directional control valve in the conventional open center circuit, and the load characteristics of the actuator Can be controlled according to the flow rate, and a cushion effect against the hydraulic pressure fluctuation can be obtained.
[0138]
Further, the bleed valve spools 811 to 814 and the bleed valve spools 821 to 824 are switched over in a direction above the direction switching valve spool 331 for right running, the direction switching valve spool 332 for left running, and the direction switching valve spool 333 for turning. Since the position is shifted in the front-rear direction with respect to the valve spools 331, 332, and 333, and is substantially staggered with respect to the direction switching valve spools 331, 332, 333, the distance in the height direction between the direction switching valve spool and the bleed valve spool Is shortened, even if there are many bleed valve spools, various valve elements can be rationally arranged without interference in the limited volume of the housing 202, and the entire valve device can be made compact. .
[0139]
【The invention's effect】
ADVANTAGE OF THE INVENTION According to the present invention, in a hydraulic system that can realize a merging circuit and a priority circuit with a simple configuration in a closed center circuit and that can independently control the priority and metering characteristics in a combined operation, It is possible to provide a directional control valve device that can perform flow control according to the load characteristics of each of the actuators and has a compact valve structure without a large valve structure.
[Brief description of the drawings]
FIG. 1 is a circuit diagram of a hydraulic system using a direction switching valve device according to an embodiment of the present invention.
FIG. 2 is a diagram showing an operation system of the hydraulic system shown in FIG.
FIG. 3 is a configuration diagram of a controller of the hydraulic system shown in FIG. 1;
4 is an external view of a hydraulic shovel on which the hydraulic system shown in FIG. 1 is mounted.
FIG. 5 is a diagram showing a relationship between an operation state and an auxiliary valve operating position when the auxiliary valve is controlled by a single operation in the hydraulic system shown in FIG. 1;
FIG. 6 is a diagram showing a relationship between an operation state and an auxiliary valve operating position when controlling the auxiliary valve in the traveling combined operation in the hydraulic system shown in FIG. 1;
FIG. 7 is a diagram showing a relationship between an operation state and an auxiliary valve operating position when controlling an auxiliary valve in a combined swing operation in the hydraulic system shown in FIG. 1;
8 is a diagram showing a relationship between an operation state and an auxiliary valve operating position when controlling the auxiliary valve in the front two combined operation in the hydraulic system shown in FIG. 1;
FIG. 9 is a diagram showing a relationship between an operation state and an auxiliary valve operating position when controlling the auxiliary valve in the front three combined operations in the hydraulic system shown in FIG. 1;
FIG. 10 is a view showing an opening curve of an auxiliary valve of the hydraulic system shown in FIG. 1;
11 is a diagram showing details of a bleed valve and a pump control valve in the hydraulic system shown in FIG. 1.
FIG. 12 is a diagram showing an opening curve of a bleed valve.
FIG. 13 is a diagram showing an opening curve of a bleed valve.
FIG. 14 is an expanded view showing left and right side surfaces of the directional control valve device according to the embodiment of the present invention.
FIG. 15 is a top view of the direction switching valve device.
FIG. 16 is a right side view of the direction switching valve device.
FIG. 17 is a left side view of the direction switching valve device.
FIG. 18 is a sectional view taken along line AA of FIGS. 16 and 17;
FIG. 19 is a sectional view taken along line BB of FIGS. 16 and 17;
FIG. 20 is a sectional view taken along line CC of FIGS. 16 and 17;
FIG. 21 is a sectional view taken along line DD of FIGS. 16 and 17;
FIG. 22 is a sectional view taken along line EE in FIGS. 16 and 17;
FIG. 23 is a sectional view taken along line FF of FIGS. 16 and 17;
FIG. 24 is a sectional view taken along line GG of FIGS. 16 and 17;
FIG. 25 is a sectional view taken along line HH in FIGS. 16 and 17;
FIG. 26 is a sectional view taken along line II of FIGS. 16 and 17;
27 is an enlarged view of a poppet valve and a pilot spool portion of the left traveling auxiliary valve shown in FIG. 20;
28 shows details of an anti-drift valve related to the boom directional control valve shown in FIG. 24.
FIG. 29 is a sectional view taken along the line KK of FIGS. 16 and 17;
FIG. 30 is an enlarged view of a pump control valve portion shown in FIG.
[Explanation of symbols]
1a, b Hydraulic pump
2a, 2b regulator
3 Boom cylinder
4 Arm cylinder
5 bucket cylinder
6 Swing motor
7 Left running motor
8 Right running motor
69 Spare actuator
9 Boom directional control valve
10 Arm directional switching valve
11 Directional switching valve for bucket
12 Direction switching valve for turning
13 Direction switching valve for left running
14 Right direction switching valve
70 Spare directional switching valve
16 Load check valve
17 Fixed aperture
25a, 25b bleed line
29 tanks
30a, 30b pump line
31a, 31b Proportional solenoid valve
32a, 32b proportional solenoid valve
33a, 33b proportional solenoid valve
34a, 34b proportional solenoid valve
35a, 35b proportional solenoid valve
41a, 41b Pilot pressure sensor
42a, 42b Pilot pressure sensor
43a, 43b Pilot pressure sensor
44a, 44b Pilot pressure sensor
45a, 45b Pilot pressure sensor
46a, 46b Pilot pressure sensor
47a, 47b Pilot pressure sensor
77, 78 Pump control valve
81-88 Bleed valve
91a, 91b Auxiliary valve
92a, 92b Pilot pressure signal
93a, 93b Feeder line
101a, 101b Auxiliary valve
102a, 102b Pilot pressure signal
103a, 103b Feeder line
111a, 111b Auxiliary valve
112a, 112b Pilot pressure signal
113a, 113b Feeder line
122a, 122b Pilot pressure signal
123b feeder line
131a, 131b Auxiliary valve
132a, 132b Pilot pressure signal
133a, 133b Feeder line
142a, 142b Pilot pressure signal
143a feeder line
701a, 701b Auxiliary valve
702a, 702b Pilot pressure signal
703a, 703b Feeder line
711a, 711b Pilot pressure signal
712a, 712b Pilot pressure signal
713a Pilot pressure signal
201 Top
202 bottom
203 Right side
204 Left side
205 front end
206 rear end face
207 housing
225 1st side block
226 Second side block
231a to 237a; 231b to 237b Pilot port
241a to 245a; 241b to 245b Pilot port
251a to 254a; 251b to 254b Pilot port
261a-264a; 261b-264b Pilot port
301, 302 Pump passage
303, 304 Tank passage
331-337 Directional valve spool
361,371 Feeder passage
362, 372a, 372b Feeder passage
363,372 Feeder passage
364-367, 374a, 374b-377a, 377b Feeder passage
391a, 391b to 397a, 397b Inflow side notch
401a, 401b to 407a, 407b Outflow side notch
442a, 442b to 447a, 447b Poppet valve
462a, 462b to 467a, 467b Pilot spool
562a, 562b Closure plug
565a, 564b Overload relief valve
573 Anti-drift valve
576a, 576b Overload relief valve
593 Anti-drift valve
596a, 596b Overload relief valve
801 and 802 first and second bypass passages
811-814; 821-824 Bleed valve spool
815,825 Valve body of pump control valve
831a, 831b to 834a, 834b notch
841a, 841b-844a, 844b Notch

Claims (6)

First and second pump passages arranged side by side at substantially the same height, and arranged side by side across the pump passages at a height separated from the first and second pump passages First and second directional control valve spools, first and second feeder passages connecting the first and second pump passages to a pump port of the first directional control valve spool, and the first and second directional control valve spools; First and second pumps are respectively arranged in a direction crossing the second pump passage to control the flow of the pressure oil supplied from the first and second pump passages to the first and second feeder passages, respectively. A second auxiliary valve poppet valve, a third feeder passage connecting the first pump passage to a pump port of the second directional control valve spool, and a third feeder passage arranged in a direction crossing the first pump passage. Is it the first pump passage In the directional control valve device and a third auxiliary valve poppet valves that assist controlling a flow of the hydraulic fluid supplied to said third feeder passage,
The first and second directional control valve spools are arranged in the same direction as the first and second pump passages at a height position opposite to the first and second pump passages with the first and second directional control valve spools therebetween. First and second bypass passages, the first and second pump passages being connected to the first and second pump passages, and the other end being connected to a tank passage.
First and second bleed valve spools arranged side by side in a direction crossing the first bypass passage, and decreasing an opening area as an operation stroke of the first and second directional control valve spools increases;
A third bleed valve spool arranged in a direction crossing the second bypass passage, and decreasing an opening area as an operation stroke of the first directional control valve spool increases,
The first and second bleed valve spools are staggered on the first bypass passage side with respect to the first and second directional control valve spools, and the third bleed valve spool is connected to the second bypass passage. A directional control valve device characterized in that the directional control valve devices are arranged in a staggered manner with respect to the first and second directional control valve spools on the side. 2. The directional control valve device according to claim 1, wherein the first to third bleed valve spools include, at both ends thereof, a pressure receiving portion to which a pilot pressure signal for causing a corresponding directional control valve spool to stroke is guided. A directional switching valve device operated by a pilot pressure signal. 2. The directional control valve device according to claim 1, wherein the first and second auxiliary valve poppets are located at a height opposite to the first directional control valve spool across the first and second pump passages. First and second auxiliary valve pilot spools arranged in the same direction as the valve, and the first and second auxiliary valve pilot spools at a height opposite to the second direction switching valve spool with the first and second pump passages interposed therebetween. A directional switching valve device further comprising a third auxiliary valve poppet valve and a third auxiliary valve pilot spool arranged in the same direction. 2. The directional switching valve device according to claim 1, wherein the first and second bypass passages are arranged at substantially the same height as the first and second bypass passages and downstream of the first and second bypass passages. A directional control valve device, further comprising: a pump control valve. First and second pump passages arranged side by side at substantially the same height position, and arranged at a height position separated from the first and second pump passages in a direction crossing these pump passages. First and second directional control valve spools, first and second feeder passages connecting the first and second pump passages to a pump port of the first directional control valve spool, and the first and second directional control valve spools; First and second pumps are respectively arranged in a direction crossing the second pump passage to control the flow of the pressure oil supplied from the first and second pump passages to the first and second feeder passages, respectively. A second auxiliary valve poppet valve, third and fourth feeder passages connecting the first and second pump passages to a pump port of the second directional control spool, and the first and second pumps In the direction across the passage And a third and fourth auxiliary valve poppet valves that auxiliary control the flow of pressure oil supplied from the first and second pump passages to the third and fourth feeder passages, respectively. In the directional switching valve device,
The first and second directional control valve spools are arranged in the same direction as the first and second pump passages at a height position opposite to the first and second pump passages with the first and second directional control valve spools therebetween. First and second bypass passages, the first and second pump passages being connected to the first and second pump passages, and the other end being connected to a tank passage.
First and second bleed valve spools arranged side by side in a direction crossing the first bypass passage, and decreasing an opening area as an operation stroke of the first and second directional control valve spools increases;
Third and fourth bleed valve spools arranged side by side in a direction crossing the second bypass passage, the opening areas decreasing as the operation strokes of the first and second directional control valve spools increase. ,
The first and second bleed valve spools are arranged in a zigzag manner with respect to the first and second directional control valve spools on the first bypass passage side, and the third and fourth bleed valve spools are disposed on the first and second bleed valve spools. 2. A directional control valve device, wherein the first and second directional control valve spools are arranged in a zigzag manner on a side of the second bypass passage. First and second pump passages arranged side by side at substantially the same height position, and arranged at a height position separated from the first and second pump passages in a direction crossing these pump passages. A plurality of directional control valve spools including directional control valve spools for right traveling, left traveling, turning, bucket, boom, arm, and a directional switching spool for the right traveling through the first pump passage; A first feeder passage communicating with a pump port of the second direction, a second and third feeder passage communicating the first and second pump passages with a pump port of the directional control valve spool for left traveling, A fourth feeder passage connecting the second pump passage to a pump port of the turning directional control valve spool; and connecting the first and second pump passages to a pump port of the directional control valve spool for the bucket. Fifth and sixth feeder passages, and seventh and eighth feeder passages connecting the first and second pump passages to a pump port of the boom directional control spool. Ninth and tenth feeder passages connecting a second pump passage to a pump port of the directional control valve spool for the arm, and a first and a second pump passage are arranged in a direction crossing the first and second pump passages, respectively. First and second auxiliary valve poppet valves for respectively controlling the flow of pressure oil supplied from the second pump passage to the second and third feeder passages; and the first and second pumps Third and fourth auxiliary valves arranged in a direction crossing the passages, respectively, for supplementarily controlling the flow of pressure oil supplied from the first and second pump passages to the fifth and sixth feeder passages, respectively; Poppet And respectively arranged in a direction crossing the first and second pump passages, and assist the flow of the pressure oil supplied from the first and second pump passages to the seventh and eighth feeder passages, respectively. Fifth and sixth auxiliary valve poppet valves to be controlled and disposed in a direction crossing the first and second pump passages, respectively, from the first and second pump passages to the ninth and tenth feeder passages. A directional switching valve device comprising: a seventh and an eighth auxiliary valve poppet valve for auxiliary controlling the flow of the supplied pressure oil, respectively.
The first and second directional control valve spools are arranged in the same direction as the first and second pump passages at a height position opposite to the first and second pump passages with the first and second directional control valve spools therebetween. First and second bypass passages, the first and second pump passages being connected to the first and second pump passages, and the other end being connected to a tank passage.
At least one of right-hand traveling direction switching spools of the right-hand traveling, left traveling, turning, bucket, boom, and arm direction switching valve spools arranged in a direction crossing the first bypass passage; First to fourth bleed valve spools each of which has an opening area that decreases as an operation stroke of each of the directional valve spools increases, for four directional valve spools including valves;
A direction switching valve for turning at least one of the direction switching valve spools for the right running, the left running, the turning, the bucket, the boom, and the arm, which are arranged side by side in a direction crossing the second bypass passage; And four directional control valve spools, including the remaining directional control valve spools not included in the four directional control valve spools, wherein the opening area decreases as the operation stroke of each directional control valve spool increases. 8 bleed valve spools,
The first to fourth bleed valve spools are arranged on the first bypass passage side in three directions out of the direction switching valve spools for the right running, the left running, the turning, the bucket, the boom, and the arm. The fifth to eighth bleed valve spools are arranged in a zigzag manner with respect to the switching valve spool, and the fifth to eighth bleed valve spools for the right traveling, the left traveling, the turning, the bucket, the boom, and the arm are provided on the second bypass passage side. A directional control valve device, wherein three directional control valve spools of the directional control valve spools are staggered.

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