Multi-control valve

Abstract

This multi-control valve controls the flow of a working fluid to two ports of a first hydraulic cylinder. The multi-control valve comprises: a first control spool that is connected to a first hydraulic pump, a tank, and one of two ports, and that controls the flow of the working fluid supplied to and discharged from the one port; a second control spool that is connected to the first hydraulic pump, the tank, and the other of the two ports, and that controls the flow of the working fluid supplied to and discharged from the other port; and a sub-spool that is connected to the second hydraulic pump and the other port, and that controls the flow rate of the working fluid supplied from the second hydraulic pump to the other port. The first and second control spools and the sub-spool control the flow rate of the working fluid independently of each other, and the sub-spool regenerates the working fluid discharged from the other port in the one port.

Description

Multi-Control Valve

[0001] The present disclosure relates to a multi-control valve that controls the flow of hydraulic fluid to a hydraulic cylinder.

[0002] Construction machinery such as excavators equipped with multiple hydraulic cylinders is equipped with a hydraulic drive device that controls the flow of hydraulic fluid to each of the hydraulic cylinders. One example of a hydraulic drive device is the hydraulic drive system described in Patent Document 1. In the hydraulic drive system described in Patent Document 1, a meter-in control valve and a meter-out control valve are connected to one hydraulic cylinder. The meter-in control valve controls the flow rate of hydraulic fluid flowing from the pump to the hydraulic cylinder, i.e., the meter-in flow rate, and the meter-out flow rate controls the flow rate of hydraulic fluid discharged from the hydraulic cylinder to a tank, i.e., the meter-out flow rate.

[0003] Japanese Patent Application Laid-Open No. 2022-47627

[0004] The hydraulic drive system of Patent Document 1 includes, for example, a multi-control valve, which includes a meter-in control valve, a meter-out control valve, and the like. In the hydraulic drive system of Patent Document 1, the multi-control valve is provided with one meter-in control valve and one meter-out control valve for each hydraulic cylinder. However, other configurations of multi-control valves are also possible. That is, in other configurations of multi-control valves, multiple control valves are connected to one port of the hydraulic cylinder to supply more hydraulic fluid. On the other hand, supplying more hydraulic fluid means that more hydraulic fluid is discharged from the hydraulic cylinder. Therefore, it is necessary to effectively utilize the discharged hydraulic fluid to reduce energy consumption in the multi-control valve. Furthermore, even if the energy consumption of a multi-control valve is reduced, if the multi-control valve becomes larger, it will be less mountable on construction machinery and less energy-efficient. Therefore, it is desirable to reduce both energy consumption and size in the multi-control valve described above.

[0005] Therefore, an object of the present disclosure is to provide a multi-control valve that can reduce both energy consumption and size.

[0006] The multi-control valve of the first disclosure controls the flow of hydraulic fluid to two ports of a first hydraulic cylinder and includes a first control spool connected to a first hydraulic pump, a tank, and one of the two ports and controls the flow of hydraulic fluid supplied to and discharged from the one port; a second control spool connected to the first hydraulic pump, the tank, and the other of the two ports and controls the flow of hydraulic fluid supplied to and discharged from the other port; and a sub-spool connected to a second hydraulic pump and the other port and controls the flow rate of hydraulic fluid supplied from the second hydraulic pump to the other port, wherein the first and second control spools and the sub-spool control the flow rate of hydraulic fluid independently of each other, and the sub-spool regenerates hydraulic fluid discharged from the other port to the one port.

[0007] According to the first disclosure, the sub-spool regenerates hydraulic fluid discharged from the other port to one port. Therefore, the sub-spool can regenerate hydraulic fluid discharged from the other port to one port. This reduces the energy consumption of the multi-control valve. Furthermore, the sub-spool controls the flow rate of hydraulic fluid supplied from the second hydraulic pump to the other port. Therefore, the sub-spool, together with the second control spool, supplies a greater flow rate of hydraulic fluid to the other port. Therefore, because the sub-spool can supply and regenerate hydraulic fluid, the number of parts related to regeneration can be reduced. This prevents the multi-control valve from becoming too large.

[0008] The multi-control valve of the second disclosure controls the flow of hydraulic fluid to each of a first hydraulic cylinder and a second hydraulic cylinder having two ports, and further includes a first control spool connected to a hydraulic pump, a tank, and one of the two ports of the first hydraulic cylinder, and controls the flow of hydraulic fluid supplied to and discharged from the one port of the first hydraulic cylinder; a second control spool connected to the other of the two ports of the hydraulic pump, the tank, and the first hydraulic cylinder, and controls the flow of hydraulic fluid supplied to and discharged from the other port of the first hydraulic cylinder; and a regenerative valve that supplies hydraulic fluid discharged from the second hydraulic cylinder to at least one of the first control spool and the second control spool.

[0009] According to the second disclosure, the regenerative valve supplies hydraulic fluid discharged from the second hydraulic cylinder to at least one of the first control spool and the second control spool. Therefore, hydraulic fluid discharged from the second hydraulic cylinder can be regenerated to the first hydraulic cylinder. This reduces energy consumption in the multi-control valve. Furthermore, because the regenerated hydraulic fluid is regenerated to the first hydraulic cylinder via at least one of the first control spool and the second control spool, it is possible to ensure controllability of the flow rate of hydraulic fluid supplied to the first hydraulic cylinder when regenerating hydraulic fluid.

[0010] The multi-control valve of the first disclosure can reduce both energy consumption and size.

[0011] According to the multi-control valve of the second disclosure, it is possible to reduce energy consumption and ensure controllability of the supply flow rate to the first hydraulic cylinder during regeneration.

[0012] The above and other objects, features, and advantages of the present invention will become apparent from the following detailed description of preferred embodiments, which proceeds with reference to the accompanying drawings.

[0013] FIG. 1 is a perspective view showing a multi-control valve provided in a hydraulic drive device of a first embodiment according to the present disclosure. FIG. 2 is a circuit diagram showing a hydraulic circuit formed in the multi-control valve. FIG. 3 is a side view of the multi-control valve of FIG. 1 as seen from one side in the height direction. FIG. 4 is a side view of the multi-control valve of FIG. 1 as seen from the other side in the height direction. FIG. 5 is a perspective view of the multi-control valve of FIG. 1 as seen from a different direction. FIG. 6 is a cross-sectional view of the multi-control valve of FIG. 4 taken along line A-A. FIG. 7 is a cross-sectional view of the multi-control valve of FIG. 4 taken along line B-B. FIG. 8 is a cross-sectional view of the multi-control valve of FIG. 4 taken along line C-C. FIG. 9 is a cross-sectional view of the multi-control valve of FIG. 4 taken along line D-D.

[0014] A multi-control valve 1 according to an embodiment of the present disclosure will be described below with reference to the drawings. Note that the concepts of directions used in the following description are used for convenience of explanation and do not limit the orientation of the configuration of the present disclosure to those directions. Furthermore, the multi-control valve 1 described below is merely one embodiment of the present disclosure. Therefore, the present disclosure is not limited to the embodiment, and additions, deletions, and modifications are possible within the scope of the present disclosure.

[0015] <Multi-Control Valve> The multi-control valve 1 shown in FIG. 1 is provided in a construction machine or the like. The construction machine is, for example, a shovel, and is provided with multiple actuators 2 to 7 as shown in FIG. 2. In this embodiment, the shovel is provided with a first traveling motor 2, a second traveling motor 3, a swing motor 4, a boom cylinder 5, an arm cylinder 6, and a bucket cylinder 7. However, the shovel may be provided with actuators other than the six described above, and the construction machine may also be a wheel loader, a crane, or the like. The first traveling motor 2 and the second traveling motor 3 respectively operate a pair of crawlers (not shown) provided on the traveling device. The swing motor 4 rotates a rotating body (not shown) provided on the traveling device. Furthermore, the boom cylinder 5, the arm cylinder 6, and the bucket cylinder 7 respectively operate the boom, the arm, and the bucket (all not shown).

[0016] As shown in FIG. 2 , the multi-control valve 1 is, for example, a multi-control valve for a two-pump system and is connected to two hydraulic pumps 8 and 9. Hydraulic fluid is supplied to the multi-control valve 1 from the two hydraulic pumps 8 and 9. The multi-control valve 1 is also connected to a plurality of actuators 2 to 7. Each of the actuators 2 to 7 has two ports 2a to 7a and 2b to 7b. The multi-control valve 1 controls the flow of hydraulic fluid to the two ports 2a to 7a and 2b to 7b in each of the actuators 2 to 7. That is, the multi-control valve 1 controls the direction (i.e., flow direction) of hydraulic fluid supplied to and discharged from the two ports 2a to 7a and 2b to 7b in each of the actuators 2 to 7, as well as the flow rate of the supplied and discharged hydraulic fluid. More specifically, the multi-control valve 1 can independently control the flow rate of hydraulic fluid supplied to and discharged from the two ports 4a to 7a and 4b to 7b in each of the swing motor 4, boom cylinder 5, arm cylinder 6, and bucket cylinder 7.

[0017] The multi-control valve 1 configured as above includes a valve block 11 and a plurality of spools 12 to 25, as shown in Figures 3 and 4. In this embodiment, the multi-control valve 1 includes 14 spools 12 to 25. The number of spools 12 to 25 included in the multi-control valve 1 is not limited to 14, and may be 13 or less or 15 or more. The multi-control valve 1 also includes a boom regeneration valve element 26.

[0018] As shown in FIGS. 1 and 5 , the valve block 11 is formed, for example, in the shape of a rectangular parallelepiped. The valve block 11 has various passages 31 to 54, which will be described in detail later. The valve block 11 also has pump ports 31a and 32a on each side surface in the width direction perpendicular to the depth direction. Each of the pump ports 31a and 32a is connected to a hydraulic pump 8 or 9. The valve block 11 also has two tank ports 33a and 33b and four connection ports 35a, 36a, 38a, and 39a on a surface on one side in the depth direction (e.g., the rear surface). The tank 30 is connected to the tank ports 33a and 33b. The valve block 11 also has a plurality of connection ports 41a, 41b, 43a, 45a, 45b, 45a, 49a, 50a, 52a, and 53a on each side surface in the width direction. The connection ports 35a, 36a, 38a, 39a, 41a, 41b, 43a, 45a, 45b, 45a, 49a, 50a, 52a, and 53a are connected to the ports 2a to 7a and 2b to 7b of the plurality of actuators 2 to 7, respectively.

[0019] 3 and 4 control the flow of hydraulic fluid to each of the actuators 2 to 7. Each of the spools 12 to 24, which will be described in more detail, is associated with each of the actuators 2 to 7 and controls the flow of hydraulic fluid supplied to and discharged from the corresponding actuator 2 to 7. In this embodiment, the spools 12 to 25 include a first traveling spool 12, a second traveling spool 13, a first arm head side spool 14, a second arm head side spool 15, a first arm rod side spool 16, a second arm rod side spool 17, a first boom head side spool 18, a second boom head side spool 19, a boom rod side spool 20, a first swing spool 21, a second swing spool 22, a bucket head side spool 23, and a bucket rod side spool 24. Each of the spools 12 to 24 is slidably inserted into the valve block 11. In this embodiment, the spools 12 to 24 are inserted into the valve block 11 so as to be slidable in the height direction, which is an example of a first direction. The height direction is a direction perpendicular to the depth direction and width direction. The spools 12 to 24 control the flow of hydraulic fluid by stroking. In addition to the spools 12 to 24, a confluence spool 25 is also inserted into the valve block 11 so as to be slidable in the height direction.

[0020] As shown in Figures 1 and 5, the multi-control valve 1 also includes a plurality of solenoid valves 12a to 24a and 12b to 25b. Each of the solenoid valves 12a to 24a and 12b to 25b is provided in the valve block 11 in correspondence with a corresponding one of the spools 12 to 25 (see also Figures 3 and 4, for example). Each of the solenoid valves 12a to 24a and 12b to 25b outputs a pilot pressure to the corresponding spool 12 to 25 in response to an input signal. This causes each of the solenoid valves 12a to 24a and 12b to 25b to stroke the corresponding spool 12 to 25. The multi-control valve 1 configured in this manner has a hydraulic circuit 1a as follows:

[0021] <Hydraulic Circuit in Multi-Control Valve> The hydraulic circuit 1a in the multi-control valve 1 will be described below with reference to FIG. 2. The valve block 11 has two main passages 31, 32 and a tank passage 33. Each main passage 31, 32 has a pump port 31a, 32a. The first main passage 31 is connected to the first hydraulic pump 8 via a first hydraulic pump port 31a, and the second main passage 32 is connected to the second hydraulic pump 9 via a second hydraulic pump port 32a. The first main passage 31 is connected to the spools 12, 14, 16, 19, 21, and 22 in parallel. The second main passage 32 is connected to the spools 13, 15, 17, 18, 20, 23, and 24 in parallel. The tank passage 33 is connected to the tank 30 via tank ports 33a and 33b (see FIG. 1). Each of the spools 12 to 25 will be described in more detail below.

[0022] [Travel Spool] The first travel spool 12 is connected to the first hydraulic pump 8. More specifically, the first travel spool 12 is connected to the first main passage 31 via a first travel passage 34 having a check valve 34a therein, and is further connected to the first hydraulic pump 8 via the first main passage 31. The first travel spool 12 is also connected to a tank passage 33. The first travel spool 12 controls the flow of hydraulic fluid supplied to and discharged from the first travel motor 2. More specifically, the first travel motor 2 has a first supply / discharge port 2a and a second supply / discharge port 2b. The first travel spool 12 is connected to the first supply / discharge port 2a via a first supply / discharge passage 35, and to the second supply / discharge port 2b via a second supply / discharge passage 36. The first traveling spool 12 receives pilot pressures output from the solenoid valves 12a, 12b in opposing directions and strokes to a position corresponding to the pilot pressures of the solenoid valves 12a, 12b. By stroking, the first traveling spool 12 switches the connection destinations of the supply / discharge ports 2a, 2b to the first main passage 31 and the tank passage 33, respectively, and adjusts the opening degree of the first traveling spool 12. In this way, the first traveling spool 12 controls the flow of hydraulic fluid to the first supply / discharge port 2a and the second supply / discharge port 2b of the first traveling motor 2.

[0023] The second traveling spool 13 is connected to the second hydraulic pump 9. More specifically, the second traveling spool 13 is connected to the second main passage 32 via a second traveling passage 37 having a check valve 37a interposed therein, and is further connected to the second hydraulic pump 9 via the second main passage 32. The second traveling spool 13 is also connected to the tank passage 33. The second traveling spool 13 controls the flow of hydraulic fluid supplied to and discharged from the second traveling motor 3. More specifically, the second traveling motor 3 has a first supply / discharge port 3a and a second supply / discharge port 3b. The second traveling spool 13 is connected to the first supply / discharge port 3a via a first supply / discharge passage 38 and to the second supply / discharge port 3b via a second supply / discharge passage 39. The second traveling spool 13 receives pilot pressures output from the solenoid valves 13a, 13b in opposing directions, and strokes to a position corresponding to the pilot pressures of the solenoid valves 13a, 13b. The second traveling spool 13 switches the connection destinations of the supply / discharge ports 3 a, 3 b to the second main passage 32 and the tank passage 33, respectively, by stroking, and also adjusts the opening degree of the second traveling spool 13. In this way, the second traveling spool 13 controls the flow of hydraulic fluid to the first supply / discharge port 3 a and the second supply / discharge port 3 b of the second traveling motor 3.

[0024] [Arm Spool] The first arm head-side spool 14, which is an example of a first control spool, is connected to the first hydraulic pump 8. More specifically, the first arm head-side spool 14 is connected to the first main passage 31 via a first arm passage 40 in which a check valve 40a is interposed, and is further connected to the first hydraulic pump 8 via the first main passage 31. The first arm head-side spool 14 is also connected to the tank 30 via a tank passage 33. The first arm head-side spool 14 controls the flow of hydraulic fluid supplied to and discharged from the head-side port 6a of the arm cylinder 6. The arm cylinder 6, which is an example of a first hydraulic cylinder, has two ports 6a, 6b, and the head-side port 6a is one of the two ports 6a, 6b. More specifically, the first arm head-side spool 14 is connected to the head-side port 6a via a head-side passage 41, which is an example of a connecting passage. The first arm head-side spool 14 receives pilot pressures output from the solenoid valves 14a, 14b in opposing directions, and strokes to a position corresponding to the pilot pressures of the solenoid valves 14a, 14b. By stroking, the first arm head-side spool 14 switches the connection destination of the head-side port 6a between the first main passage 31 and the tank passage 33. This allows the first arm head-side spool 14 to supply hydraulic fluid from the first hydraulic pump 8 to the head-side port 6a of the arm cylinder 6, or to discharge hydraulic fluid from the head-side port 6a of the arm cylinder 6 to the tank 30. The first arm head-side spool 14 also adjusts its opening. This allows the first arm head-side spool 14 to control the flow rate of hydraulic fluid supplied to or discharged from the head-side port 6a of the arm cylinder 6.

[0025] The second arm head-side spool 15 is connected to the second hydraulic pump 9. More specifically, the second arm head-side spool 15 is connected to the second main passage 32 via a second arm passage 42 in which a check valve 42a is disposed, and is further connected to the second hydraulic pump 9 via the second main passage 32. The second arm head-side spool 15 is also connected to the tank 30 via a tank passage 33. The second arm head-side spool 15 controls the flow of hydraulic fluid to the head-side port 6a of the arm cylinder 6. More specifically, the second arm head-side spool 15 is connected in parallel to the first arm head-side spool 14 via a head-side passage 41. The second arm head-side spool 15 is also connected to the head-side port 6a via the head-side passage 41. The second arm head-side spool 15 receives pilot pressures output from the solenoid valves 15a, 15b in opposing directions, and strokes to a position corresponding to the pilot pressures of the solenoid valves 15a, 15b. By stroking, the second arm head-side spool 15 switches the connection destination of the head-side port 6a to either the second main passage 32 or the tank passage 33. This allows the second arm head-side spool 15 to supply hydraulic fluid from the second hydraulic pump 9 to the head-side port 6a of the arm cylinder 6, or to discharge hydraulic fluid from the head-side port 6a of the arm cylinder 6 to the tank 30. The second arm head-side spool 15 also adjusts its opening. This allows the second arm head-side spool 15 to control the flow rate of hydraulic fluid supplied to or discharged from the head-side port 6a of the arm cylinder 6.

[0026] The first arm rod side spool 16, which is an example of a second control spool, is connected to the first hydraulic pump 8. More specifically, the first arm rod side spool 16 is connected to the first main passage 31 via a first arm passage 40, and further connected to the first hydraulic pump 8 via the first main passage 31. More specifically, the first arm rod side spool 16 is connected to the downstream side of the check valve 40a in the first arm passage 40 so as to be parallel to the first arm head side spool 14, and is connected to the first main passage 31 together with the first arm head side spool 14 via the check valve 40a. The first arm rod side spool 16 is also connected to the tank 30 via a tank passage 33. The first arm rod side spool 16 controls the flow of hydraulic fluid to the rod side port 6b, which is the other port 6b of the arm cylinder 6. More specifically, the first arm rod side spool 16 is connected to the rod side port 6b via a rod side passage 43. The first arm rod-side spool 16 receives pilot pressures output from the solenoid valves 16a, 16b in opposing directions, and strokes to a position corresponding to the pilot pressures of the solenoid valves 16a, 16b. By stroking, the first arm rod-side spool 16 switches the connection of the rod-side port 6b to either the first main passage 31 or the tank passage 33. This allows the first arm rod-side spool 16 to supply hydraulic fluid from the first hydraulic pump 8 to the rod-side port 6b of the arm cylinder 6, or to discharge hydraulic fluid from the rod-side port 6b of the arm cylinder 6 to the tank 30. The first arm rod-side spool 16 also adjusts its opening. This allows the first arm rod-side spool 16 to control the flow of hydraulic fluid supplied to or discharged from the rod-side port 6b of the arm cylinder 6.

[0027] The second arm rod side spool 17, which is an example of a sub-spool, is connected to the second hydraulic pump 9. More specifically, the second arm rod side spool 17 is connected to the second main passage 32 via a second arm passage 42, and is further connected to the second hydraulic pump 9 via the second main passage 32. More specifically, the second arm rod side spool 17 is connected to the downstream side of the check valve 42a in the second arm passage 42 so as to be in parallel with the second arm head side spool 15, and is connected to the second main passage 32 together with the second arm head side spool 15 via the check valve 42a. The second arm rod side spool 17 controls the flow rate of hydraulic fluid supplied to the rod side port 6b of the arm cylinder 6. The second arm rod side spool 17 also regenerates hydraulic fluid discharged from the rod side port 6b of the arm cylinder 6 to the head side port 6a. More specifically, the second-arm rod-side spool 17 is connected in parallel to the first-arm rod-side spool 16 in the rod-side passage 43. The second-arm rod-side spool 17 is connected to the rod-side port 6b via the rod-side passage 43. A regeneration passage 55 having a check valve 55a therein is also connected to the second-arm rod-side spool 17. The regeneration passage 55 is connected to the head-side port 6a, and hydraulic fluid discharged from the rod-side port 6b is regenerated to the head-side port 6a via the regeneration passage 55. In this embodiment, the regeneration passage 55 is connected to the head-side passage 41, and is connected to the head-side port 6a via the head-side passage 41.

[0028] The second-arm rod-side spool 17 strokes between a supply position A1 and a regeneration position A2. The supply position A1 is a position where the second hydraulic pump 9 and the rod-side port 6b are connected, and the regeneration position A2 is a position where the rod-side port 6b is connected to the head-side port 6a. In other words, the second-arm rod-side spool 17 strokes to switch the connection destination of the rod-side port 6b between the second main passage 32 and the head-side port 6a (more specifically, the regeneration passage 55). The second-arm rod-side spool 17 receives pilot pressures output from the solenoid valves 17a, 17b in opposing directions, and strokes to a position corresponding to the pilot pressures of the solenoid valves 17a, 17b. As a result, the second arm rod-side spool 17 can supply hydraulic fluid from the second hydraulic pump 9 to the rod-side port 6b of the arm cylinder 6, and can also regenerate hydraulic fluid discharged from the rod-side port 6b of the arm cylinder 6 to the head-side port 6a. The second arm rod-side spool 17 also adjusts its opening. As a result, the second arm rod-side spool 17 controls the flow rate of hydraulic fluid supplied to the rod-side port 6b of the arm cylinder 6, and also controls the flow rate of hydraulic fluid regenerated to the head-side port 6a.

[0029] The spools 14 to 17 configured in this manner stroke independently of one another. Therefore, the spools 14 to 17 can independently control the flow of hydraulic fluid supplied to and discharged from the head-side port 6a and the rod-side port 6b of the arm cylinder 6. That is, the spools 14 to 17 can independently control the meter-in flow rate and the meter-out flow rate for each of the head-side port 6a and the rod-side port 6b of the arm cylinder 6. Furthermore, by stroking both of the arm rod-side spools 16 and 17, hydraulic fluid from the second hydraulic pump 9 can be supplied to the rod-side port 6b in addition to hydraulic fluid from the first hydraulic pump 8. Therefore, the arm rod-side spools 16 and 17 can supply a larger flow rate to the rod-side port 6b of the arm cylinder 6 than when only one spool 16 is stroked. The same applies to the arm head-side spools 14 and 15.

[0030] [Boom Spool] The first boom head-side spool 18, which is an example of a third control spool, is connected to the second hydraulic pump 9. More specifically, the first boom head-side spool 18 is connected to the second main passage 32 via a first boom passage 44 in which a check valve 44a is disposed, and is further connected to the second hydraulic pump 9 via the second main passage 32. The first boom head-side spool 18 is also connected to the tank 30 via a tank passage 33. The first boom head-side spool 18 controls the flow of hydraulic fluid to the head-side port 5a of the boom cylinder 5. The boom cylinder 5, which is an example of a second hydraulic cylinder, has two ports 5a and 5b, and the head-side port 5a is, for example, one port 5a of the two ports 5a and 5b. More specifically, the first boom head-side spool 18 is connected to the head-side port 5a via a head-side passage 45. The first boom head-side spool 18 receives pilot pressures output from the solenoid valves 18a, 18b in opposing directions and strokes to a position corresponding to the pilot pressures of the solenoid valves 18a, 18b. By stroking, the first boom head-side spool 18 switches the connection of the head-side port 5a to either the second main passage 32 or the tank passage 33. This allows the first boom head-side spool 18 to supply hydraulic fluid from the second hydraulic pump 9 to the head-side port 5a of the boom cylinder 5, or to discharge hydraulic fluid from the head-side port 5a of the boom cylinder 5 to the tank 30. The first boom head-side spool 18 also adjusts its opening. This allows the first boom head-side spool 18 to control the flow rate of hydraulic fluid supplied to or discharged from the head-side port 5a of the boom cylinder 5.

[0031] The second boom head side spool 19 is connected to the first hydraulic pump 8. More specifically, the second boom head side spool 19 is connected to the first main passage 31 via a second boom passage 46 in which a check valve 46a is disposed, and is connected to the first hydraulic pump 8 via the first main passage 31. The second boom head side spool 19 is also connected to the tank 30 via a tank passage 33. The second boom head side spool 19 controls the flow of hydraulic fluid to the head side port 5a of the boom cylinder 5. More specifically, the second boom head side spool 19 is connected in parallel to the first boom head side spool 18 in the head side passage 45. The second boom head side spool 19 is also connected to the head side port 5a via the head side passage 45. The second boom head-side spool 19 receives pilot pressures output from the solenoid valves 19a, 19b in opposing directions and strokes to a position corresponding to the pilot pressures of the solenoid valves 19a, 19b. By stroking, the second boom head-side spool 19 switches the connection destination of the head-side port 5a between the first main passage 31 and the tank passage 33, and adjusts the aperture of the second boom head-side spool 19. This allows the second boom head-side spool 19 to supply hydraulic fluid from the first hydraulic pump 8 to the head-side port 5a of the boom cylinder 5, or to discharge hydraulic fluid from the head-side port 5a of the boom cylinder 5 to the tank 30. The second boom head-side spool 19 also adjusts its aperture. This allows the second boom head-side spool 19 to control the flow rate of hydraulic fluid supplied to or discharged from the head-side port 5a of the boom cylinder 5.

[0032] The boom rod side spool 20, which is an example of a fourth control spool, is connected to the second hydraulic pump 9. More specifically, the boom rod side spool 20 is connected to the second main passage 32 via the first boom passage 44, and further connected to the second hydraulic pump 9 via the second main passage 32. More specifically, the boom rod side spool 20 is connected downstream of the check valve 44a in parallel with the first boom head side spool 18, and is connected to the second main passage 32 together with the first boom head side spool 18 via the check valve 44a. The boom rod side spool 20 is also connected to the tank 30 via the tank passage 33. The boom rod side spool 20 controls the flow of hydraulic fluid to the rod side port 5b, which is the other port 5b of the boom cylinder 5. More specifically, the boom rod side spool 20 is connected to the rod side port 5b via the rod side passage 47. The boom rod-side spool 20 receives pilot pressures output from the solenoid valves 20a, 20b in opposing directions, and strokes to a position corresponding to the pilot pressures of the solenoid valves 20a, 20b. By stroking, the boom rod-side spool 20 switches the connection destination of the rod-side port 5b to either the second main passage 32 or the tank passage 33. This allows the boom rod-side spool 20 to supply hydraulic fluid from the second hydraulic pump 9 to the rod-side port 5b of the boom cylinder 5, or to discharge hydraulic fluid from the rod-side port 5b of the boom cylinder 5 to the tank 30. The boom rod-side spool 20 also adjusts its opening. This allows the boom rod-side spool 20 to control the flow rate of hydraulic fluid supplied to or discharged from the rod-side port 5b of the boom cylinder 5.

[0033] The spools 18-20 configured in this manner stroke independently of one another. Therefore, the spools 18-20 can independently control the flow of hydraulic fluid supplied to and discharged from the head-side port 5a and the rod-side port 5b of the boom cylinder 5. That is, the spools 18-20 can independently control the meter-in flow rate and the meter-out flow rate for each of the head-side port 5a and the rod-side port 5b of the boom cylinder 5. Furthermore, by stroking both of the boom head-side spools 18, 19, hydraulic fluid from the first hydraulic pump 8 can be supplied to the head-side port 5a in addition to hydraulic fluid from the second hydraulic pump 9. Therefore, by stroking both of the spools 18, 19, a greater flow rate can be supplied to the head-side port 5a of the boom cylinder 5 than when only one spool 18 is stroked.

[0034] [Swivel Spool] The first swing spool 21 is connected to the first hydraulic pump 8. More specifically, the first swing spool 21 is connected to the first main passage 31 via a swing passage 48 having a check valve 48a interposed therein, and is further connected to the first hydraulic pump 8 via the first main passage 31. The first swing spool 21 is also connected to the tank 30 via a tank passage 33. The first swing spool 21 controls the flow of hydraulic fluid to the first supply / discharge port 4a of the swing motor 4. The swing motor 4 has two ports 4a, 4b, and the first supply / discharge port 4a is one of the two ports 4a, 4b, 4a. More specifically, the first swing spool 21 is connected to the first supply / discharge port 4a via a first supply / discharge passage 49. The first swing spool 21 receives pilot pressures output from the solenoid valves 21a, 21b in opposing directions and strokes to a position corresponding to the pilot pressures of the solenoid valves 21a, 21b. By stroking, the first swing spool 21 switches the connection of the first supply / discharge port 4a between the first main passage 31 and the tank passage 33. This allows the first swing spool 21 to supply hydraulic fluid from the first hydraulic pump 8 to the first supply / discharge port 4a of the swing motor 4, or to discharge hydraulic fluid from the first supply / discharge port 4a of the swing motor 4 to the tank 30. The first swing spool 21 also adjusts its opening. This allows the first swing spool 21 to control the flow of hydraulic fluid supplied to or discharged from the first supply / discharge port 4a of the swing motor 4.

[0035] The second swing spool 22 is connected to the first hydraulic pump 8. More specifically, the second swing spool 22 is connected to the first main passage 31 via a swing passage 48, and further connected to the first hydraulic pump 8 via the first main passage 31. More specifically, the second swing spool 22 is connected in the swing passage 48 downstream of the check valve 48a in parallel with the first swing spool 21, and is connected together with the second swing spool 22 to the first main passage 31 via the check valve 48a. The second swing spool 22 is also connected to the tank 30 via a tank passage 33. The second swing spool 22 controls the flow of hydraulic fluid to the second supply / discharge port 4b, which is the other port 4b of the swing motor 4. More specifically, the second swing spool 22 is connected to the second supply / discharge port 4b via a second supply / discharge passage 50. The second swing spool 22 receives pilot pressures output from the solenoid valves 22a, 22b in opposing directions and strokes to a position corresponding to the pilot pressures of the solenoid valves 22a, 22b. By stroking, the second swing spool 22 switches the connection of the second supply / discharge port 4b to either the first main passage 31 or the tank passage 33. This allows the second swing spool 22 to supply hydraulic fluid from the first hydraulic pump 8 to the second supply / discharge port 4b of the swing motor 4, or to discharge hydraulic fluid from the second supply / discharge port 4b of the swing motor 4 to the tank 30. The second swing spool 22 also adjusts its opening. This allows the second swing spool 22 to control the flow of hydraulic fluid supplied to or discharged from the second supply / discharge port 4b of the swing motor 4.

[0036] The spools 21, 22 also stroke independently of each other. Therefore, the spools 21, 22 can independently control the flow of hydraulic fluid supplied to and discharged from the supply / discharge ports 4a, 4b of the swing motor 4. That is, the spools 21, 22 can independently control the meter-in flow rate and the meter-out flow rate for the supply / discharge ports 4a, 4b of the swing motor 4.

[0037] [Bucket Spool] The bucket head-side spool 23 is connected to the second hydraulic pump 9. Explaining in more detail, the bucket head-side spool 23 is connected to the second main passage 32 via a bucket passage 51 in which a check valve 51a is disposed, and is further connected to the second hydraulic pump 9 via the second main passage 32. The bucket head-side spool 23 is also connected to the tank 30 via a tank passage 33. The bucket head-side spool 23 controls the flow of hydraulic fluid to the head-side port 7a of the bucket cylinder 7. The bucket cylinder 7 has two ports 7a, 7b, and the head-side port 7a is one of the two ports 7a, 7b. Explaining in more detail, the bucket head-side spool 23 is connected to the head-side port 7a via a head-side passage 52. The bucket head-side spool 23 receives pilot pressures output from the solenoid valves 23a, 23b in opposing directions, and strokes to a position corresponding to the pilot pressures of the solenoid valves 23a, 23b. By stroking, the bucket head-side spool 23 switches the connection destination of the head-side port 7a to either the second main passage 32 or the tank passage 33. This allows the bucket head-side spool 23 to supply hydraulic fluid from the second hydraulic pump 9 to the head-side port 7a of the bucket cylinder 7, or to discharge hydraulic fluid from the head-side port 7a of the bucket cylinder 7 to the tank 30. The bucket head-side spool 23 also adjusts its opening. This allows the bucket head-side spool 23 to control the flow rate of hydraulic fluid supplied to or discharged from the head-side port 7a of the bucket cylinder 7.

[0038] The bucket rod side spool 24 is connected to the second hydraulic pump 9. Explaining in more detail, the bucket rod side spool 24 is connected to the second main passage 32 via a bucket passage 51, and further connected to the second hydraulic pump 9 via the second main passage 32. Explaining in even more detail, the bucket rod side spool 24 is connected in the bucket passage 51 downstream of the check valve 51 a so as to be in parallel with the bucket head side spool 23, and is connected to the second main passage 32 together with the bucket head side spool 23 via the check valve 51 a. The bucket rod side spool 24 is also connected to the tank 30 via a tank passage 33. The bucket rod side spool 24 controls the flow of hydraulic fluid to the rod side port 7b, which is the other port 7b of the bucket cylinder 7. Explaining in more detail, the bucket rod side spool 24 is connected to the rod side port 7b via a rod side passage 53. The bucket rod-side spool 24 receives pilot pressures output from the solenoid valves 24a, 24b in opposing directions, and strokes to a position corresponding to the pilot pressures of the solenoid valves 24a, 24b. By stroking, the bucket rod-side spool 24 switches the connection destination of the rod-side port 7b to either the second main passage 32 or the tank passage 33. This allows the bucket rod-side spool 24 to supply hydraulic fluid from the second hydraulic pump 9 to the rod-side port 7b of the bucket cylinder 7, or to discharge hydraulic fluid from the rod-side port 7b of the bucket cylinder 7 to the tank 30. The bucket rod-side spool 24 also adjusts its opening. This allows the bucket rod-side spool 24 to control the flow of hydraulic fluid supplied to or discharged from the rod-side port 7b of the bucket cylinder 7.

[0039] The spools 23, 24 also stroke independently of each other. Therefore, the spools 23, 24 can independently control the flow of hydraulic fluid supplied to and discharged from the head side port 7 a and the rod side port 7 b of the bucket cylinder 7. That is, the spools 23, 24 can independently control the meter-in flow rate and the meter-out flow rate for the head side port 7 a and the rod side port 7 b of the bucket cylinder 7, respectively.

[0040] [Converging Spool] The converging spool 25 is disposed in a converging passage 54 connecting the two main passages 31, 32, and opens and closes the converging passage 54. The converging spool 25 receives pilot pressure output from the solenoid valve 25b in a direction against the biasing force of a spring mechanism 26d, which will be described in detail later, and strokes to a position corresponding to the pilot pressure of the solenoid valve 25b. The converging spool 25 opens and closes the converging passage 54 by stroking, and also adjusts the opening degree of the converging spool 25. In this way, the converging spool 25 merges the hydraulic fluid from the first main passage 31 to the second main passage 32 and in the opposite direction, and also controls the flow rate of the hydraulic fluid to be merged.

[0041] [Boom Regenerative Valve Body] The boom regenerative valve body 26, which is an example of a regenerative valve body, supplies hydraulic fluid discharged from the boom cylinder 5 to the first arm head side spool 14 and the first arm rod side spool 16. As a result, the boom regenerative valve body 26 regenerates hydraulic fluid discharged from the boom cylinder 5 to the arm cylinder 6 via the first arm head side spool 14 and the first arm rod side spool 16. More specifically, the boom regenerative valve body 26 is connected to the head side passage 45 and the first arm passage 40. More specifically, the boom regenerative valve body 26 is connected to the head side passage 45 so as to be parallel to the spools 18, 19. Furthermore, the boom regenerative valve body 26 is connected to the downstream side of the check valve 40a in the first arm passage 40 so as to be parallel to the spools 14, 16. The boom regenerative valve body 26 regenerates hydraulic fluid discharged from the head side port 5a of the boom cylinder 5 to the arm cylinder 6. In this embodiment, the boom regenerative valve element 26 is a poppet-type valve element that opens and closes in response to the pilot pressure output from the solenoid valve 26a. The boom regenerative valve element 26 also adjusts its opening degree in response to the pilot pressure. As a result, the boom regenerative valve element 26 regenerates hydraulic fluid from the head-side port 5a of the boom cylinder 5 to the head-side port 6a or the rod-side port 6b of the arm cylinder 6, and also controls the regenerated flow rate.

[0042] <Specific Configuration of Multi-Control Valve> The specific configuration of the multi-control valve 1 will be described below. As shown in Figures 3 and 4, the multi-control valve 1 includes a valve block 11 and multiple spools 12-25, as described above. Furthermore, as shown in Figures 6 to 9, the multi-control valve 1 includes multiple spool covers 12c-25c, multiple spring mechanisms 12d-25d, and multiple solenoid valves 12a-24a, 12b-25b. The valve block 11 is formed, for example, in a substantially rectangular parallelepiped shape, as shown in Figures 1 and 5. The valve block 11 includes a block main body 11a and multiple spool holes 11b, 11c.

[0043] The block body 11a is formed, for example, in a roughly rectangular parallelepiped shape. In this embodiment, the block body 11a includes a first block member 11d and a second block member 11e. The block body 11a can be divided into the first block member 11d and the second block member 11e in the depth direction. However, the block body 11a does not necessarily have to be divided into the first block member 11d and the second block member 11e. The block body 11a has multiple spool holes 11b formed as follows.

[0044] As shown in FIGS. 3 and 4 , multiple spool holes 11b are formed on both height-wise side surfaces of the block body 11a. More specifically, multiple spool holes 11b, 11c are arranged in two rows on each height-wise side surface of the block body 11a. In this embodiment, for example, six spool holes 11b (hereinafter referred to as “first spool holes 11b”) are formed on one height-wise side surface of the block body 11a, and eight spool holes 11c (hereinafter referred to as “second spool holes 11c”) are formed on the other height-wise side surface of the block body 11a. The spool holes 11b, 11c on each side surface are arranged in two rows in the width direction, which is an example of a row direction. In each row, three first spool holes 11b are arranged in the depth direction on one side surface, and four second spool holes 11c are arranged in the depth direction on the other side surface. In each row, the spool holes 11b, 11c are aligned in a row with each other in the depth direction. In this embodiment, two first spool holes 11b are formed on one side of the first block member 11d, and four second spool holes 11c are formed on the other side. Four spool holes 11b, 11c are formed on each side of the second block member 11e. Each of the spool holes 11b, 11c extends in the height direction from each side surface of the block body 11a in the height direction.

[0045] As shown in FIGS. 6 to 9, the spool holes 11b and 11c are arranged to correspond to one another. More specifically, six of the second spool holes 11c are arranged to correspond to one of the first spool holes 11b and extend toward the corresponding first spool hole 11b. A pair of spool holes 11b and 11c, each consisting of a corresponding first spool hole 11b and a corresponding second spool hole 11c, are arranged in a vertical line. In this embodiment, the pair of spool holes 11b and 11c are aligned in a vertical line so that their axes coincide with each other. The pair of spool holes 11b and 11c are formed in the valve block 11 at a distance from one another in the vertical direction, forming a partition wall 11f between them.

[0046] The spools 12 to 25 are inserted into the valve block 11 as follows. That is, each of the spools 12 to 25 is slidably inserted into the first spool hole 11b and the second spool hole 11c of the valve block 11. In this embodiment, each of the spools 16, 17, 20, 22, 24, and 25 is slidably inserted into the first spool hole 11b. The spools 16, 17, 20, 22, and 24 form inner pilot chambers 16e, 17e, 20e, 22e, and 24e on the bottom side of the first spool hole 11b. The spools 12 to 15, 18, 19, 21, and 23 are slidably inserted into the second spool hole 11c. The spools 12 to 15, 18, 19, 21, and 23 form inner pilot chambers 12e to 15e, 18e, 19e, 21e, and 23e on the bottom side of the second spool hole 11c, respectively. Pilot pressure is introduced into each of the inner pilot chambers 12e to 24e, and each of the spools 12 to 24 receives the pilot pressure of the inner pilot chambers 12e to 24e in a direction toward the opening of each spool hole 11b, 11c (hereinafter referred to as "axially outward").

[0047] In this embodiment, spools 20, 17, and 24 are slidably inserted into the first spool holes 11b in the row on one side in the width direction, starting from one side in the depth direction. Spools 25, 16, and 22 are slidably inserted into the first spool holes 11b in the row on the other side in the width direction, starting from one side in the depth direction. Spools 13, 18, 15, and 23 are slidably inserted into the second spool holes 11c in the row on one side in the width direction, starting from one side in the depth direction. Spools 12, 19, 14, and 21 are slidably inserted into the second spool holes 11c in the row on the other side in the width direction, starting from one side in the depth direction. As a result, the second arm rod-side spool 17 and the second arm head-side spool 15 are aligned in a vertical line, and are disposed on one and the other sides in the vertical direction, respectively. In addition, the combinations of the boom rod side spool 20 and the first boom head side spool 18, and the first arm rod side spool 16 and the first arm head side spool 14 are lined up in a row in the height direction and are respectively located on one side and the other side in the height direction. In addition, the combinations of the junction spool 25 and the second boom head side spool 19, the bucket rod side spool 24 and the bucket head side spool 23, and the second swivel spool 22 and the first swivel spool 21 are lined up in a row in the height direction and are respectively located on one side and the other side in the height direction.

[0048] The spool covers 12c to 25c are provided on the block body 11a so as to cover the openings of the spool holes 11b and 11c. That is, the spool covers 12c to 25c are provided on the block body 11a so as to cover the corresponding spools 12 to 25. More specifically, spool covers 16c, 17c, 20c, 22c, 24c, and 25c are provided on one side surface of the block body 11a in the height direction, and spool covers 12c to 15c, 18c, 19c, 21c, and 23c are provided on the other side surface in the height direction. In this embodiment, the spool covers 12c to 25c are formed integrally with each other to form a double cover. However, the adjacent spool covers 12c to 25c do not necessarily have to be formed integrally with each other. Outer pilot chambers 12f to 25f are formed inside the spool covers 12c to 25c. The outer pilot chambers 12f to 25f correspond to the respective spools 12 to 25. Pilot pressure is introduced into the outer pilot chambers 12f to 25f, and the pilot pressure in each of the outer pilot chambers 12f to 24f acts on the corresponding spool 12 to 25 in a direction (hereinafter referred to as "axially inward") that resists the pilot pressure in the inner pilot chambers 12e to 24e.

[0049] The spring mechanisms 12d to 25d are housed in the spool covers 12c to 25c, respectively. In this embodiment, the spring mechanisms 12d to 25d are housed in the outer pilot chambers 12f to 25f, respectively. The spring mechanisms 12d to 25d correspond to the spools 12 to 25, and bias the corresponding spools 12 to 25. More specifically, the spring mechanisms 12d to 25d bias the spools 12 to 25 in the direction opposite to the stroke direction of the corresponding spools 12 to 25. This returns the spools 12 to 25 to their neutral positions.

[0050] The first solenoid valves 12a to 24a correspond to the spools 12 to 24, respectively. The first solenoid valves 12a to 24a output pilot pressures corresponding to signals input to the corresponding spools 12 to 24. In this embodiment, the first solenoid valves 12a to 24a are attached to the spool covers 12c to 24c of the corresponding spools 12 to 24, and are connected to the inner pilot chambers 12e to 24e, respectively. The first solenoid valves 12a to 24a output pilot pressures to the corresponding inner pilot chambers 12e to 24e.

[0051] The second solenoid valves 12b to 25b also correspond to the spools 12 to 25, respectively. The second solenoid valves 12b to 25b output pilot pressures according to signals input to the corresponding spools 12 to 25. In this embodiment, the second solenoid valves 12b to 25b are attached to the spool covers 12c to 25c of the corresponding spools 12 to 25, and are connected to the outer pilot chambers 12f to 25f, respectively. The second solenoid valves 12b to 25b output pilot pressures to the corresponding outer pilot chambers 12f to 25f.

[0052] The pilot pressures output from the first solenoid valves 12a to 24a and second solenoid valves 12b to 25b configured in this manner act in opposing directions on the corresponding spools 12 to 25. The biasing forces of the spring mechanisms 12d to 25d also act in opposing directions on the corresponding spools 12 to 25 against the first solenoid valves 12a to 24a and second solenoid valves 12b to 25b. Therefore, each spool 12 to 25 strokes to a position where the pilot pressure of each solenoid valve 12a to 24a, 12b to 25b and the biasing force of each spring mechanism 12d to 25d are balanced. As a result, each spool 12 to 25 controls the flow of hydraulic fluid in accordance with the signal input to each solenoid valve 12a to 24a, 12b to 25b.

[0053] The various passages 31-54 and the pump ports 31a, 32a are formed in the block body 11a as follows. That is, the first main passage 31 and the second main passage 32 are arranged apart on one and the other widthwise sides, sandwiching the first spool hole 11b and the second spool hole 11c, as shown in FIG. 6. The first main passage 31 and the second main passage 32 extend in the depth direction (see also FIGS. 7 to 9) and open to one and the other widthwise side surfaces via the pump ports 32a, 31a, respectively. In addition, the various passages 33-54 are formed in the block body 11a to realize the hydraulic circuit 1a described above. An example of the arrangement of the various passages 33-54 will be described below.

[0054] 6 , the first traveling passage 34 and the second traveling passage 37 are adjacent to the first traveling spool 12 and the second traveling spool 13, respectively, and are spaced apart on one and the other widthwise sides. The first traveling passage 34 is connected to the first main passage 31 and the first traveling spool 12, and the second traveling passage 37 is connected to the second main passage 32 and the second traveling spool 13. In the first traveling spool 12, first and second supply and discharge passages 35, 36 are connected to both axial sides of the first traveling passage 34, and the tank passage 33 is further connected to the axially outer sides of these passages. The first and second supply and discharge passages 35, 36 are connected to the first supply and discharge port 2a and the second supply and discharge port 2b, respectively, via first and second supply and discharge connection ports 35a, 36a that open on one depth-wise surface of the valve block 11. Similarly, the second traveling spool 13 has first and second supply / discharge passages 38, 39 connected to both axial sides of the second traveling passage 37, and further connected to the axial outside of these passages is the tank passage 33. The first and second supply / discharge passages 38, 39 are connected to the first supply / discharge port 3a and the second supply / discharge port 3b, respectively, via first and second supply / discharge connection ports 38a, 39a that open on a surface of the valve block 11 on one side in the depth direction.

[0055] As shown in FIG. 7 , the first boom passage 44 and the second boom passage 46 are disposed apart from each other on one and the other widthwise sides. The first boom passage 44 is disposed adjacent to the first boom head side spool 18 and the boom rod side spool 20. The first boom passage 44 is connected to the second main passage 32 and branches off from the second main passage 32 midway to connect to the first boom head side spool 18 and the boom rod side spool 20. A check valve 44a is disposed in the first boom passage 44 at its branching point. The first boom head side spool 18 is connected to a head side passage 45 and a tank passage 33, in that order, axially outward from the first boom passage 44. The boom rod side spool 20 is connected to a rod side passage 47 and a tank passage 33, in that order, axially outward from the first boom passage 44. The rod-side passage 47 is connected to the rod-side port 5b of the boom cylinder 5 via a rod-side connection port 47a that opens on one side surface in the width direction. The head-side passage 45 extends to the other side surface in the width direction, straddling the second boom head-side spool 19, and is connected to the head-side port 5a of the boom cylinder 5 via head-side connection ports 45a, 45b that open on both side surfaces in the width direction.

[0056] The second boom passage 46 is arranged adjacent to the second boom head side spool 19. The second boom passage 46 is connected to the first main passage 31 and the second boom head side spool 19 with a check valve 46a interposed therebetween. The second boom head side spool 19 is also connected to the head side passage 45 and the tank passage 33 axially outward of the second boom passage 46. Furthermore, the merging passage 54 is arranged adjacent to the other widthwise side of the merging spool 25. The merging passage 54 connects the second main passage 32 and the first main passage 31 with the merging spool 25 interposed therebetween.

[0057] As shown in FIG. 8 , the first arm passage 40 and the second arm passage 42 are spaced apart on one and the other widthwise sides. The first arm passage 40 is disposed adjacent to the first arm head-side spool 14 and the first arm rod-side spool 16. The first arm passage 40 is connected to the first main passage 31 and branches off midway from the first main passage 31 to connect to the first arm head-side spool 14 and the first arm rod-side spool 16. A check valve 40a is interposed in the first arm passage 40 at its branching point. The first arm passage 40 is formed to connect the two spools 14, 16 downstream of the check valve 40a and is connected to the head-side passage 45 via the boom regeneration valve element 26 downstream of the check valve 40a. Furthermore, the head-side passage 41 and the tank passage 33 are connected to the first arm head-side spool 14, in that order, axially outward of the first arm passage 40. Furthermore, the first arm rod-side spool 16 is connected in this order to a rod-side passage 43 and a tank passage 33 axially outward from the first arm passage 40 .

[0058] The second arm passage 42 is disposed adjacent to the second arm head-side spool 15 and the second arm rod-side spool 17. The second arm passage 42 is connected to the second main passage 32 and branches off midway from the second main passage 32 to connect to the second arm head-side spool 15 and the second arm rod-side spool 17. A check valve 42a is disposed in the second arm passage 42 at its branching point. The head-side passage 41 and the tank passage 33 are connected to the second arm head-side spool 15, in that order, axially outward from the second arm passage 42. That is, the head-side passage 41 is disposed on the other side in the height direction of the valve block 11. The rod-side passage 43 and the regenerative passage 55 are connected to the second arm rod-side spool 17, axially outward from the second arm passage 42. The head-side passage 41 extends in the width direction so as to straddle the two arm head-side spools 14, 15. The head-side passage 41 also penetrates the valve block 11 and is connected to the head-side port 5a of the arm cylinder 6 via head-side connection ports 41a, 41b that open on both widthwise side surfaces. The rod-side passage 47 extends in the other widthwise direction so as to straddle the first arm rod-side spool 16. The rod-side passage 43 is connected to the rod-side port 5b of the arm cylinder 6 via a rod-side connection port 43a that opens on the other widthwise side surface.

[0059] Furthermore, the regeneration passage 55 extends in the height direction from the second-arm rod-side spool 17 toward the head-side passage 41. More specifically, the second-arm rod-side spool 17 is located on one side of the valve block 11 in the height direction, and the regeneration passage 55 extends in the height direction from one side of the valve block 11 in the height direction toward the head-side passage 41. The regeneration passage 55 is connected to the head-side passage 41 via a check valve 51a. In this embodiment, the regeneration passage 55 first extends in the other width direction from the second-arm rod-side spool 17 and then bends. Furthermore, the regeneration passage 55 has the check valve 51a interposed at the bent portion, and then extends linearly from there in the other height direction toward the head-side passage 41. By extending linearly in this manner, the regeneration passage 55 can be formed more easily.

[0060] As shown in FIG. 9 , the bucket passage 51 and the swing passage 48 are disposed apart from each other on one and the other side of the width direction. The swing passage 48 is disposed adjacent to the first swing spool 21 and the second swing spool 22. The swing passage 48 is connected to the first main passage 31 and branches off midway from the first main passage 31 to connect to the first swing spool 21 and the second swing spool 22. A check valve 48a is disposed in the swing passage 48 at its branching point. A first supply / discharge passage 49 and a tank passage 33 are connected to the first swing spool 21, in that order, axially outward from the swing passage 48. A second supply / discharge passage 50 and a tank passage 33 are connected to the second swing spool 22, in that order, axially outward from the swing passage 48. The first supply / discharge passage 49 is connected to the first supply / discharge port 4a of the swing motor 4 via a first supply / discharge connection port 49a that opens on the other side surface in the width direction. The second supply / discharge passage 50 is connected to the second supply / discharge port 4b of the swing motor 4 via a second supply / discharge connection port 50a that opens on the other side surface in the width direction.

[0061] The bucket passage 51 is disposed adjacent to the bucket head-side spool 23 and the bucket rod-side spool 24. The bucket passage 51 is connected to the second main passage 32 and branches off midway from the second main passage 32 to connect to the bucket head-side spool 23 and the bucket rod-side spool 24. A check valve 51a is disposed in the bucket passage 51 at its branching point. A head-side passage 52 and a tank passage 33 are connected in this order axially outward from the bucket passage 51 to the bucket head-side spool 23. A rod-side passage 53 and a tank passage 33 are connected in this order axially outward from the bucket passage 51 to the bucket rod-side spool 24. The head-side passage 52 is connected to a head-side port 7a of the bucket cylinder 7 via a head-side connection port 52a that opens on one side surface in the width direction. The rod-side passage 53 is connected to a rod-side port 7b of the bucket cylinder 7 via a rod-side connection port 53a that opens on one side surface in the width direction.

[0062] <Flow of Hydraulic Fluid in the Multi-Control Valve> The multi-control valve 1 operates as follows when driving each of the actuators 2 to 7. That is, when driving the traveling device, the multi-control valve 1 outputs pilot pressure from at least one of the solenoid valves 12a, 12b, 13a, and 13b. For example, when pilot pressure is output from the first solenoid valves 12a and 13a, the pilot pressure is directed to the inner pilot chambers 12e and 13e, respectively, and the traveling spools 12 and 13 are actuated. As a result, hydraulic fluid is supplied from the hydraulic pump 8 to the first traveling motor 2 via the first traveling spool 12, and from the hydraulic pump 9 to the second traveling motor 3 via the second traveling spool 13. This drives the traveling device.

[0063] Furthermore, when rotating the swing body, the multi-control valve 1 operates as follows. That is, the multi-control valve 1 outputs pilot pressure from one of the solenoid valves 21a, 21b, 22a, and 22b. For example, when pilot pressure is output from the solenoid valves 21a and 22b, the pilot pressure is introduced into the pilot chambers 21f and 22e, and the swing motor 4 is activated. At this time, hydraulic fluid is supplied from the hydraulic pump 8 to the first supply / discharge port 4a via the first swing spool 21, and is further discharged from the second supply / discharge port 4b to the second swing spool 22 and into the tank 30. The first swing spool 21 and the second swing spool 22 can independently stroke, and their respective openings can be adjusted independently. Therefore, the multi-control valve 1 can independently control the flow rates of the fluid flowing through the first supply / discharge port 4a and the second supply / discharge port 4b, enabling more precise control of the swing motor 4.

[0064] Furthermore, when operating the arm, the multi-control valve 1 operates as follows. For example, when extending the arm cylinder 6, the multi-control valve 1 outputs pilot pressure from the solenoid valves 14b and 17a. This leads to the pilot pressure being directed to the pilot chambers 14f and 17e. As a result, hydraulic fluid from the first hydraulic pump 8 is directed to the head-side port 6a via the first arm head-side spool 14. Meanwhile, hydraulic fluid is discharged from the rod-side port 6b, and the discharged hydraulic fluid is directed to the regeneration passage 55 via the second arm rod-side spool 17. Furthermore, the hydraulic fluid is regenerated to the head-side port 6a via the regeneration passage 55. In this way, hydraulic fluid from the first hydraulic pump 8 and hydraulic fluid regenerated from the rod-side port 6b are directed to the head-side port 6a of the arm cylinder 6. This causes the arm cylinder 6 to extend. Furthermore, when a larger flow rate is required to flow through the head-side port 6a of the arm cylinder 6, pilot pressure is also output from the solenoid valve 15b. This leads to pilot pressure being introduced into the pilot chamber 15f, and hydraulic fluid from the second hydraulic pump 9 can also be introduced to the head side port 6a of the arm cylinder 6 via the second arm head side spool 15. This allows a larger flow rate of hydraulic fluid to flow through the head side port 6a of the arm cylinder 6. Furthermore, the multi-control valve 1 outputs pilot pressure from the solenoid valve 16a to the pilot chamber 16e, and discharges a portion of the hydraulic fluid discharged from the rod side port 6b to the tank 30 via the first arm rod side spool 16. This controls the flow rate of hydraulic fluid regenerated in the head side port 6a. On the other hand, when the arm cylinder 6 is to be retracted, the multi-control valve 1 outputs pilot pressure from the solenoid valves 14a and 16b. This leads to pilot pressure being introduced into the pilot chambers 14e and 16f, and the arm cylinder 6 retracts. Furthermore, the output of pilot pressure from the solenoid valves 15a and 17b allows a larger flow rate of hydraulic fluid to flow through the rod side port 6b of the arm cylinder 6.

[0065] In the arm cylinder 6 that extends and retracts in this manner, hydraulic fluid is supplied to and discharged from the head side port 6a via the arm head side spools 14, 15, and hydraulic fluid is supplied to and discharged from the rod side port 6b via the arm rod side spools 16, 17. Each of the spools 14 to 17 can stroke independently of one another, and their respective openings can be adjusted independently of one another. Therefore, with the multi-control valve 1, the flow rates supplied to and discharged from the head side port 6a and the rod side port 6b can also be controlled independently, allowing for more precise control of the arm cylinder 6.

[0066] Furthermore, when driving the boom, the multi-control valve 1 operates as follows. For example, when extending the boom cylinder 5, the multi-control valve 1 outputs pilot pressure from the solenoid valves 18b and 20a. This leads to the pilot pressure being directed to the pilot chambers 18f and 20e. As a result, hydraulic fluid from the second hydraulic pump 9 is directed to the head-side port 5a, extending the boom cylinder 5. Furthermore, when a larger flow rate is required through the head-side port 5a of the boom cylinder 5, the pilot pressure is also output from the solenoid valve 19b. This leads to the pilot pressure being directed to the pilot chamber 19f, and hydraulic fluid from the first hydraulic pump 8 is also directed to the head-side port 5a of the boom cylinder 5 via the second boom head-side spool 19. This allows a larger flow rate to flow through the head-side port 5a of the boom cylinder 5. On the other hand, when retracting the boom cylinder 5, the multi-control valve 1 outputs pilot pressure from the solenoid valves 18a and 20b. As a result, pilot pressure is introduced into the pilot chambers 18e and 20f, causing the boom cylinder 5 to contract.

[0067] In the boom cylinder 5 that extends and retracts in this manner, hydraulic fluid is supplied to and discharged from the head side port 5a via the boom head side spools 18, 19, and hydraulic fluid is supplied to and discharged from the rod side port 5b via the rod side spool 20. The spools 18-20 can stroke independently of one another, and their respective openings can be adjusted independently of one another. Therefore, with the multi-control valve 1, the flow rates supplied to and discharged from the head side port 5a and the rod side port 5b can also be controlled independently, allowing for more precise control of the boom cylinder 5.

[0068] Furthermore, when operating the bucket, the multi-control valve 1 operates as follows. For example, when extending the bucket cylinder 7, the multi-control valve 1 outputs pilot pressure from the solenoid valves 23b and 24a. This leads to pilot pressure being introduced into the pilot chambers 23f and 24e, causing the bucket cylinder 7 to extend. On the other hand, when retracting the bucket cylinder 7, the multi-control valve 1 outputs pilot pressure from the solenoid valves 23b and 24a. This leads to pilot pressure being introduced into the pilot chambers 23e and 24f, causing the bucket cylinder 7 to retract.

[0069] Furthermore, when the arm and boom are moved simultaneously and the boom is retracted, the multi-control valve 1 operates as follows in addition to the operations described above. That is, the multi-control valve 1 outputs pilot pressure from the solenoid valve 26a. As a result, the hydraulic fluid discharged from the head-side port 5a of the boom cylinder 5 is guided to the first arm passage 40 via the boom regeneration valve element 26. The hydraulic fluid is then guided to the arm cylinder 6 via the first arm head-side spool 14 or the first arm rod-side spool 16, that is, the hydraulic fluid is regenerated in the arm cylinder 6.

[0070] Furthermore, when the traveling device is used to cause the excavator to travel straight, the multi-control valve 1 opens the junction passage 54 via the junction spool 25. This connects the first hydraulic pump 8 and the second hydraulic pump 9. More specifically, the two main passages 31, 32 are connected to each other. This reduces the difference in hydraulic pressure between the hydraulic fluid flowing through the two main passages 31, 32, and also reduces the difference in hydraulic pressure between the hydraulic fluid guided to the first and second traveling spools 12, 13. This makes it easy to guide the same flow rate of hydraulic fluid to each traveling motor 2, 3 during straight traveling, thereby improving straight-line traveling performance.

[0071] In the multi-control valve 1 of this embodiment, the second-arm rod-side spool 17 regenerates hydraulic fluid discharged from the rod-side port 6b to the head-side port 6a. Therefore, the second-arm rod-side spool 17 can regenerate hydraulic fluid discharged from the rod-side port 6b to the head-side port 6a. This reduces the energy consumption of the multi-control valve 1. Furthermore, the second-arm rod-side spool 17 controls the flow rate of hydraulic fluid supplied from the second hydraulic pump 9 to the rod-side port 6b. Therefore, the second-arm rod-side spool 17, together with the first-arm rod-side spool 16, supplies a larger flow rate of hydraulic fluid to the rod-side port 6b. Therefore, the second-arm rod-side spool 17 can both supply and regenerate hydraulic fluid, reducing the number of components related to regeneration. This reduces the size of the multi-control valve 1.

[0072] Furthermore, in the multi-control valve 1 of this embodiment, the second-arm rod-side spool 17 strokes between the supply position A1 and the regeneration position A2, and is connected to the rod-side port 6b so as to be parallel to the first-arm rod-side spool 16. Therefore, when the second-arm rod-side spool 17 is stroked to the regeneration position A2, a portion of the hydraulic fluid discharged from the rod-side port 6b can be discharged to the tank 30 via the first-arm rod-side spool 16. Furthermore, the first-arm rod-side spool 16 controls the flow rate of the discharged hydraulic fluid, thereby controlling the flow rate of the regenerated hydraulic fluid.

[0073] Furthermore, in the multi-control valve 1 of this embodiment, the second-arm rod-side spool 17 is connected to the head-side passage 41 via the regeneration passage 55. Therefore, the hydraulic fluid regenerated from the rod-side port 6b to the head-side port 6a can be supplied to the head-side port 6a without passing through the first-arm head-side spool 14. This reduces pressure loss of the hydraulic fluid.

[0074] Furthermore, in the multi-control valve 1 of this embodiment, the second-arm rod-side spool 17 and the first-arm head-side spool 14 extend in the height direction and are disposed on one and the other sides in the height direction in the valve block 11. The head-side passage 41 is disposed on the other side in the height direction in the valve block 11, and the regeneration passage 55 extends in the height direction in the valve block 11 from the second-arm rod-side spool 17 toward the head-side passage 41. This prevents the regeneration passage 55 in the valve block 11 from becoming complicated.

[0075] Furthermore, in the multi-control valve 1 of the present embodiment, the boom regenerative valve element 26 supplies the hydraulic fluid discharged from the boom cylinder 5 to the first arm head side spool 14 and the first arm rod side spool 16. Therefore, the hydraulic fluid discharged from the boom cylinder 5 can be regenerated to the arm cylinder 6. Also, since the hydraulic fluid regenerated from the boom cylinder 5 to the arm cylinder 4 is regenerated to the arm cylinder 6 via the first arm head side spool 14 or the first arm rod side spool 16, it is possible to ensure controllability of the flow rate of the hydraulic fluid supplied to the arm cylinder 6 while regenerating the hydraulic fluid.

[0076] Furthermore, in the multi-control valve 1 of this embodiment, the boom regeneration valve element 26 is a poppet valve. This ensures controllability of the flow rate of hydraulic fluid supplied to the arm cylinder 6 when regeneration occurs from the boom cylinder 5 to the arm cylinder 6, while reducing the cost of the control valve.

[0077] Furthermore, the multi-control valve 1 of this embodiment is provided with the first boom head-side spool 18 and the boom rod-side spool 20. Therefore, by supplying hydraulic fluid to the rod-side port 5b via the boom rod-side spool 20 and discharging the hydraulic fluid from the head-side port 5a, the discharged hydraulic fluid can be regenerated to the arm cylinder 6 via the boom regeneration valve body 26. Furthermore, during regeneration, a portion of the hydraulic fluid discharged from the head-side port 5a of the boom cylinder 5 can be discharged to the tank 30 via the first boom head-side spool 18. Therefore, by having the first boom head-side spool 18 control the flow rate of hydraulic fluid discharged to the tank 30, the flow rate of hydraulic fluid to be regenerated can be adjusted.

[0078] Furthermore, in the multi-control valve 1 of this embodiment, the hydraulic fluid discharged from the head side port 6 a of the arm cylinder 6 can be regenerated to the rod side port 6 b, and the hydraulic fluid discharged from the boom cylinder 5 can be regenerated to the arm cylinder 6.

[0079] [Other Embodiments] In the multi-control valve 1 of this embodiment, the arm cylinder 6 is given as an example of the first hydraulic cylinder, but the first hydraulic cylinder may be the boom cylinder 5 or the bucket cylinder 7, or may be any other optional cylinder of the construction machine. Similarly, the boom cylinder 5 is given as an example of the second cylinder, but it may be the bucket cylinder 7, or any other hydraulic cylinder different from the first hydraulic cylinder. That is, if the first hydraulic cylinder is the boom cylinder 5, the second hydraulic cylinder may be the arm cylinder 6. Furthermore, the ports from which the regenerated and regenerated hydraulic fluid is discharged are also not limited to the ports described above, and may be the head side port 6a and the rod side port 5b.

[0080] Furthermore, although the multi-control valve 1 in this embodiment is connected to two hydraulic pumps 8, 9, it may also be connected to a single hydraulic pump. Furthermore, although the arm rod-side spools 16, 17 are connected in parallel to the rod-side passage 43 and connected to the rod-side port 6b in this embodiment, they may also be connected to the rod-side port 6b separately. Furthermore, the shapes of the regeneration passage 55 and the head-side passage 41 described above are merely examples, and any shape may be used as long as it can achieve the function of the hydraulic circuit 1a. Furthermore, the boom regeneration valve element 26 is not necessarily limited to a poppet-type valve element and may also be a spool-type valve element. Furthermore, in this embodiment, controllability of the regeneration flow rate when regenerating hydraulic fluid from the boom cylinder 5 to the arm cylinder 6 does not necessarily have to be ensured by the first arm head-side spool 14 or the first arm rod-side spool 16, but may be ensured by the boom regeneration valve element 26. In other words, the boom regeneration valve element 26 may have controllability over the flow rate of hydraulic fluid.

[0081] Furthermore, in this embodiment, the spools 18 and 19 are connected only to the head side port 5a, but they may also be connected to the rod side port 5b and configured to control the meter-in flow rate of the rod side port 5b. Similarly, the spool 20 may also be connected to the head side port 5a and configured to control the meter-out flow rate of the head side port 5a. Furthermore, both the spools 14 and 15 may be connected to the rod side port 6b and configured to control the meter-in flow rate of the rod side port 6b. Also, the spools 16 and 17 may be connected to the head side port 6a and configured to control the meter-out flow rate of the head side port 6a.

[0082] The number and shape of the spool holes 11b, 11c and the arrangement of the spools 12 to 25 in the multi-control valve 1 in this embodiment are all examples, and it is sufficient that the multi-control valve 1 is configured so that the hydraulic circuit 1a functions.

[0083] Illustrative Embodiment A multi-control valve in a first aspect controls the flow of hydraulic fluid to two ports of a first hydraulic cylinder, and includes a first control spool connected to a first hydraulic pump, a tank, and one of the two ports and controls the flow of hydraulic fluid supplied to and discharged from the one port; a second control spool connected to the first hydraulic pump, the tank, and the other of the two ports and controls the flow of hydraulic fluid supplied to and discharged from the other port; and a sub-spool connected to a second hydraulic pump and the other port and controls the flow rate of hydraulic fluid supplied from the second hydraulic pump to the other port, wherein the first and second control spools and the sub-spool control the flow rates of hydraulic fluid independently of each other, and the sub-spool regenerates hydraulic fluid discharged from the other port to the one port.

[0084] According to the above aspect, the sub-spool regenerates hydraulic fluid discharged from the other port to one port. Therefore, the sub-spool can regenerate hydraulic fluid discharged from the other port to one port. This reduces the energy consumption of the multi-control valve. Furthermore, the sub-spool controls the flow rate of hydraulic fluid supplied from the second hydraulic pump to the other port. Therefore, the sub-spool, together with the second control spool, supplies a greater flow rate of hydraulic fluid to the other port. Therefore, because the sub-spool can supply and regenerate hydraulic fluid, the number of parts related to regeneration can be reduced. This prevents the multi-control valve from becoming too large.

[0085] In a second aspect, the multi-control valve is the multi-control valve of the first aspect, wherein the sub-spool strokes between a supply position that connects the second hydraulic pump and the other port and a regeneration position that connects the other port to the one port, and is connected to the other port so as to be in parallel with the second control spool.

[0086] According to the above aspect, the sub-spool strokes between a supply position and a regeneration position and is connected to the other port in parallel with the first control spool. Therefore, when the sub-spool is stroked to the regeneration position, hydraulic fluid discharged from the other port can be discharged to the tank via the second control spool. Furthermore, the flow rate of the discharged hydraulic fluid can be controlled by the second control spool, thereby controlling the flow rate of the regenerated hydraulic fluid.

[0087] In a third aspect, the multi-control valve is the multi-control valve of the first or second aspect, wherein the sub-spool is connected to a connecting passage that connects the first control spool and the one port via a regeneration passage.

[0088] According to the above aspect, the sub-spool is connected to the connecting passage via the regeneration passage. Therefore, hydraulic fluid regenerated from the rod-side port to the head-side port can be supplied to one of the ports without passing through the first control spool. This reduces pressure loss of the hydraulic fluid.

[0089] In a fourth aspect, the multi-control valve is the multi-control valve of the third aspect, further comprising a valve block including the connecting passage and the regenerative passage, wherein the sub-spool and the first control spool extend in a first direction in the valve block and are respectively arranged on one side and the other side in the first direction, the connecting passage is arranged on one side in the first direction in the valve block, and the regenerative passage extends in the first direction from the sub-spool toward the connecting passage in the valve block.

[0090] According to the above aspect, the sub-spool and the first control spool extend in the first direction and are disposed on one side and the other side of the valve block in the first direction, respectively. The connecting passage is disposed on the other side of the valve block in the first direction, and the regenerative passage extends in the valve block from the sub-spool toward the connecting passage in the first direction. This prevents the regenerative passage in the valve block from becoming complicated.

[0091] In a fifth aspect, the multi-control valve is the multi-control valve of any one of the first to fourth aspects, further comprising a regenerative valve element that supplies hydraulic fluid discharged from a second hydraulic cylinder different from the first hydraulic cylinder to at least one of the first control spool and the second control spool.

[0092] According to the above aspect, the regenerative valve element supplies the hydraulic fluid discharged from the second hydraulic cylinder to at least one of the first control spool and the second control spool. Therefore, the hydraulic fluid discharged from the second hydraulic cylinder can be regenerated to the first hydraulic cylinder. Furthermore, the hydraulic fluid regenerated from the second hydraulic cylinder to the first hydraulic cylinder is regenerated to the first hydraulic cylinder via at least one of the first control spool and the second control spool, so that it is possible to ensure controllability of the flow rate of the hydraulic fluid supplied to the first hydraulic cylinder while regenerating the hydraulic fluid.

[0093] In a sixth aspect, in the multi-control valve of the fifth aspect, the regenerative valve element is a poppet type valve element.

[0094] According to the above aspect, the regenerative valve element is a poppet valve, which ensures controllability of the flow rate of the hydraulic fluid supplied to the first hydraulic cylinder during regeneration, while reducing the cost of the control valve.

[0095] A multi-control valve in a seventh aspect is the multi-control valve of the fifth or sixth aspect, further comprising: a third control spool connected to at least one of the first and second hydraulic pumps, the tank, and one of two ports of the second hydraulic cylinder, and configured to control the flow of working fluid supplied to or discharged from the one port of the second hydraulic cylinder; and a fourth control spool connected to the at least one hydraulic pump, the tank, and the other port of the second hydraulic cylinder, and configured to control the flow of working fluid supplied to or discharged from the other port of the second hydraulic cylinder, wherein the regenerative valve element supplies working fluid discharged from the one port of the second hydraulic cylinder to at least one of the first control spool and the second control spool.

[0096] According to the above aspect, the multi-control valve is provided with a third control spool and a fourth control spool. Therefore, by supplying hydraulic fluid to one port of the second cylinder via the fourth control spool, hydraulic fluid can be discharged from the other port of the second cylinder, and the discharged hydraulic fluid can be regenerated to the first hydraulic cylinder via the regenerative valve. Furthermore, during regeneration, a portion of the hydraulic fluid discharged from the other port of the second hydraulic cylinder can be discharged to the tank via the third control spool. Therefore, by controlling the flow rate discharged to the tank with the third control spool, the flow rate of the regenerated hydraulic fluid can be adjusted.

[0097] In an eighth aspect, in the multi-control valve of any one of the fifth to seventh aspects, the first hydraulic cylinder is an arm cylinder, and the second hydraulic cylinder is a boom cylinder.

[0098] According to the above aspect, the first hydraulic cylinder is an arm cylinder and the second hydraulic cylinder is a boom cylinder. Therefore, in the arm cylinder, hydraulic fluid discharged from one port can be regenerated to the other port, and hydraulic fluid discharged from the boom cylinder can be regenerated to the arm cylinder.

[0099] In a ninth aspect, the multi-control valve controls the flow of hydraulic fluid to each of a first hydraulic cylinder and a second hydraulic cylinder having two ports, and further includes: a first control spool connected to a hydraulic pump, a tank, and one of the two ports of the first hydraulic cylinder, and controlling the flow of hydraulic fluid supplied to and discharged from the one port of the first hydraulic cylinder; a second control spool connected to the other of the two ports of the hydraulic pump, the tank, and the first hydraulic cylinder, and controlling the flow of hydraulic fluid supplied to and discharged from the other port of the first hydraulic cylinder; and a regenerative valve that supplies hydraulic fluid discharged from the second hydraulic cylinder to at least one of the first control spool and the second control spool.

[0100] According to the above aspect, the regenerative valve supplies hydraulic fluid discharged from the second hydraulic cylinder to at least one of the first control spool and the second control spool. Therefore, hydraulic fluid discharged from the second hydraulic cylinder can be regenerated to the first hydraulic cylinder. This reduces energy consumption in the multi-control valve. Furthermore, because the regenerated hydraulic fluid is regenerated to the first hydraulic cylinder via at least one of the first control spool and the second control spool, it is possible to ensure controllability of the flow rate of hydraulic fluid supplied to the first hydraulic cylinder when hydraulic fluid is regenerated.

[0101] From the above description, many modifications and other embodiments of the present invention will be apparent to those skilled in the art. Therefore, the above description should be construed as illustrative only and is provided for the purpose of teaching those skilled in the art the best mode for carrying out the present invention. Details of the structure and / or function thereof may be substantially changed without departing from the spirit of the present invention.

Claims

1. A multi-control valve that controls the flow of hydraulic fluid to two ports of a first hydraulic cylinder, comprising: a first control spool connected to a first hydraulic pump, a tank, and one of the two ports and controlling the flow of hydraulic fluid supplied to and discharged from the one port; a second control spool connected to the first hydraulic pump, the tank, and the other of the two ports and controlling the flow of hydraulic fluid supplied to and discharged from the other port; and a sub-spool connected to a second hydraulic pump and the other port and controlling the flow rate of hydraulic fluid supplied from the second hydraulic pump to the other port, wherein the first and second control spools and the sub-spool control the flow rate of hydraulic fluid independently of each other, and the sub-spool regenerates hydraulic fluid discharged from the other port to the one port.

2. A multi-control valve as described in claim 1, wherein the sub-spool strokes between a supply position connecting the second hydraulic pump and the other port and a regeneration position connecting the other port to the one port, and is connected to the other port in parallel with the second control spool.

3. The multi-control valve according to claim 1, wherein the sub-spool is connected to a connecting passage that connects the first control spool and the one port via a regeneration passage.

4. A multi-control valve as described in claim 3, further comprising a valve block including the connecting passage and the regenerative passage, wherein the sub-spool and the first control spool extend in a first direction in the valve block and are arranged on one side and the other side of the first direction, respectively, the connecting passage is arranged on one side of the first direction in the valve block, and the regenerative passage extends in the first direction from the sub-spool towards the connecting passage in the valve block.

5. The multi-control valve according to claim 1, further comprising a regenerative valve element that supplies hydraulic fluid discharged from a second hydraulic cylinder different from the first hydraulic cylinder to at least one of the first control spool and the second control spool.

6. The multi-control valve according to claim 5, wherein the regenerative valve element is a poppet type valve element.

7. A multi-control valve as described in claim 55, comprising: a third control spool connected to at least one of the first and second hydraulic pumps, the tank, and one of two ports of the second hydraulic cylinder, and controlling the flow of hydraulic fluid supplied to and discharged from one port of the second hydraulic cylinder; and a fourth control spool connected to the at least one hydraulic pump, the tank, and the other port of the second hydraulic cylinder, and controlling the flow of hydraulic fluid supplied to and discharged from the other port of the second hydraulic cylinder, wherein the regenerative valve element supplies hydraulic fluid discharged from one port of the second hydraulic cylinder to at least one of the first control spool and the second control spool.

8. The multi-control valve according to claim 5, wherein the first hydraulic cylinder is an arm cylinder, and the second hydraulic cylinder is a boom cylinder.

9. A multi-control valve that controls the flow of hydraulic fluid to each of a first hydraulic cylinder and a second hydraulic cylinder having two ports, comprising: a first control spool connected to a hydraulic pump, a tank, and one of the two ports of the first hydraulic cylinder, and controlling the flow of hydraulic fluid supplied to and discharged from the one port of the first hydraulic cylinder; a second control spool connected to the other of the two ports of the hydraulic pump, the tank, and first hydraulic cylinder, and controlling the flow of hydraulic fluid supplied to and discharged from the other port of the first hydraulic cylinder; and a regenerative valve that supplies hydraulic fluid discharged from the second hydraulic cylinder to at least one of the first control spool and the second control spool.

Images