Multi-control valve

Abstract

A multi-control valve for controlling the flow of a hydraulic fluid with respect to a first hydraulic actuator, the multi-control valve comprising: a valve block including a first main passage connected to a first hydraulic pump; and a first control spool that is provided in the valve block and that controls the flow rate of the hydraulic fluid flowing to the first hydraulic actuator, wherein the first control spool strokes to a first supply position, at which the first main passage is connected to the first hydraulic actuator, and to a first unload position, at which the first main passage is connected to the tank.

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] A construction machine such as an excavator equipped with a plurality of hydraulic cylinders is provided 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 disclosed in Patent Document 1. In the hydraulic drive system disclosed in Patent Document 1, a hydraulic pump and an unloading valve are connected to a pump passage. The unloading valve connects the pump passage to a tank, thereby placing the hydraulic pump in an unloaded state and bleeding off the hydraulic fluid flowing through the pump passage.

[0003] Japanese Patent Application Laid-Open No. 2020-128733

[0004] The hydraulic drive system of Patent Document 1 includes, for example, a multi-control valve including multiple control spools. The hydraulic drive system is configured to be able to supply hydraulic fluid to optional actuators such as a breaker in addition to a boom cylinder, an arm cylinder, a bucket cylinder, and a swing motor. Therefore, the multi-control valve is provided with many control spools. Meanwhile, miniaturization of multi-control valves is desired to improve mountability and energy efficiency in construction machinery and the like.

[0005] Therefore, an object of the present disclosure is to provide a multi-control valve that can be prevented from becoming large.

[0006] The multi-control valve of the present disclosure is a multi-control valve that controls the flow of hydraulic fluid to a first hydraulic actuator, and comprises a valve block including a first main passage connected to a first hydraulic pump, and a first control spool provided in the valve block that controls the flow rate of hydraulic fluid flowing to the first hydraulic actuator, the first control spool stroking between a first supply position that connects the first main passage to the first hydraulic actuator and a first unload position that connects the first main passage to the tank.

[0007] According to the present disclosure, the first control spool is connected to the tank and strokes between a first supply position and a first unload position. Therefore, the first control spool can have both a supply function and an unload function. This allows the number of control spools included in the multi-control valve to be reduced, thereby preventing the multi-control valve from becoming too large.

[0008] According to the multi-control valve of the present disclosure, it is possible to prevent the valve from becoming large.

[0009] 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.

[0010] 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.

[0011] 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.

[0012] <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 equipped with multiple actuators 2 to 8 as shown in FIG. 2. In this embodiment, the shovel is equipped with a first traveling motor 2, a second traveling motor 3, a swing motor 4, a boom cylinder 5, an arm cylinder 6, a bucket cylinder 7, and a hydraulic breaker 8. However, the shovel may be equipped with actuators other than the seven 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). The hydraulic breaker 8 is a so-called crusher, an attachment attached to the arm. The hydraulic breaker 8 vibrates a chisel 8c by the hydraulic fluid supplied thereto, thereby breaking up rock formations and the like.

[0013] 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 9 and 10. Hydraulic fluid is supplied to the multi-control valve 1 from the two hydraulic pumps 9 and 10. The multi-control valve 1 is also connected to a plurality of actuators 2 to 8. Each of the actuators 2 to 8 has two ports 2a to 8a and 2b to 8b. The multi-control valve 1 controls the flow of hydraulic fluid (the direction and flow rate of hydraulic fluid) to the ports 2a to 8a and 2b to 7b of each of the actuators 2 to 8. The multi-control valve 1 can also independently control the flow rates of hydraulic fluid supplied to and discharged from the two ports 4a to 7a and 4b to 7b of the swing motor 4, boom cylinder 5, arm cylinder 6, and bucket cylinder 7, respectively.

[0014] The multi-control valve 1 configured as above includes a valve block 11 and a plurality of spools 12 to 27, as shown in Figures 3 and 4. In this embodiment, the multi-control valve 1 includes 16 spools 12 to 27. The number of spools 12 to 27 included in the multi-control valve 1 is not limited to 16, and may be 15 or less or 17 or more. The multi-control valve 1 also includes a boom regeneration valve element 28.

[0015] 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 58, 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 9 or 10. The valve block 11 also has two tank ports 33a and 33b and five connection ports 35a, 36a, 38a, 39a, and 57a on one side surface in the depth direction. The tank ports 33a and 33b are connected to the tank 30. 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, 53a, and 57a are connected to the ports 2a to 8a and 2b to 7b of the actuators 2 to 8, respectively.

[0016] 3 and 4 control the flow of hydraulic fluid to each of the actuators 2 to 8. Each of the spools 12 to 26, which will be described in more detail, is associated with each of the actuators 2 to 8 and controls the flow of hydraulic fluid supplied to and discharged from the corresponding actuator 2 to 8. In this embodiment, the spools 12 to 26 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, a bucket rod side spool 24, a first breaker spool 25, and a second breaker spool 26. Each of the spools 12 to 26 is slidably inserted into the valve block 11. In this embodiment, the spools 12 to 26 are slidably inserted into the valve block 11 in a 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 26 control the flow of hydraulic fluid by stroking. In addition to the spools 12 to 26, a confluence spool 27 is also inserted into the valve block 11 in a height direction.

[0017] 1 and 5, the multi-control valve 1 is equipped with a plurality of solenoid valves 12a to 24a and 12b to 27b. Each of the solenoid valves 12a to 24a and 12b to 27b corresponds to a corresponding spool 12 to 27. Each of the solenoid valves 12a to 24a and 12b to 27b outputs a pilot pressure to the corresponding spool 12 to 27 in response to an input signal. As a result, each of the solenoid valves 12a to 24a and 12b to 27b strokes the corresponding spool 12 to 27. The multi-control valve 1 configured in this manner has a hydraulic circuit 1a formed as follows:

[0018] <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 9 via a first hydraulic pump port 31a, and the second main passage 32 is connected to the second hydraulic pump 10 via a second hydraulic pump port 32a. The first main passage 31 is connected to the spools 12, 14, 16, 19, 21, 22, and 25 in parallel. The second main passage 32 is connected to the spools 13, 15, 17, 18, 20, 23, 24, and 26 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 27 will now be described in more detail.

[0019] [Travel Spool] The first travel spool 12 is connected to the first hydraulic pump 9. 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 interposed therein, and is further connected to the first hydraulic pump 9 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.

[0020] The second traveling spool 13 is connected to the second hydraulic pump 10. 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 10 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.

[0021] [Arm Spool] The first arm head-side spool 14 is connected to the first hydraulic pump 9. More specifically, the first arm head-side spool 14 is connected to the first main passage 31 via a first arm passage 40 having a check valve 40a interposed therein, and is further connected to the first hydraulic pump 9 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 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. 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 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 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.

[0022] The second arm head-side spool 15 is connected to the second hydraulic pump 10. More specifically, the second arm head-side spool 15 is connected to the second main passage 32 via a second arm passage 42 having a check valve 42a therein, and is further connected to the second hydraulic pump 10 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 between the second main passage 32 and the tank passage 33. This allows the second arm head-side spool 15 to supply hydraulic fluid from the second hydraulic pump 10 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.

[0023] The first arm rod side spool 16 is connected to the first hydraulic pump 9. 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 9 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 destination 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 9 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.

[0024] The second arm rod side spool 17 is connected to the second hydraulic pump 10. More specifically, the second arm rod side spool 17 is connected to the second main passage 32 via a second arm passage 42, and further connected to the second hydraulic pump 10 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 recycles 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.

[0025] 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. By stroking, the second arm rod-side spool 17 switches the connection of the rod-side port 6b between the second main passage 32 and the head-side port 6a (more specifically, the regeneration passage 55). This allows the second arm rod-side spool 17 to supply hydraulic fluid from the second hydraulic pump 10 to the rod-side port 6b of the arm cylinder 6, or to 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. This allows the second arm rod-side spool 17 to control the flow rate of hydraulic fluid supplied to the rod-side port 6b of the arm cylinder 6, and to control the flow rate of hydraulic fluid regenerated to the head-side port 6a.

[0026] 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 10 can be supplied to the rod-side port 6b in addition to hydraulic fluid from the first hydraulic pump 9. 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.

[0027] [Boom Spool] The first boom head-side spool 18 is connected to the second hydraulic pump 10. More specifically, the first boom head-side spool 18 is connected to the second main passage 32 via a first boom passage 44 having a check valve 44a interposed therein, and is further connected to the second hydraulic pump 10 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 has two ports 5a, 5b, and the head-side port 5a is, for example, one port 5a of the two ports 5a, 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 destination of the head-side port 5a between the second main passage 32 and the tank passage 33. This allows the first boom head-side spool 18 to supply hydraulic fluid from the second hydraulic pump 10 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.

[0028] The second boom head side spool 19 is connected to the first hydraulic pump 9. 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 9 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 via 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 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 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.

[0029] The boom rod side spool 20 is connected to the second hydraulic pump 10. Explaining in more detail, 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 10 via the second main passage 32. Explaining in even more detail, 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 a 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. Explaining in more detail, the boom rod side spool 20 is connected to the rod side port 5b via a 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 10 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.

[0030] 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 9 can be supplied to the head-side port 5a in addition to hydraulic fluid from the second hydraulic pump 10. 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.

[0031] [Swivel Spool] The first swing spool 21 is connected to the first hydraulic pump 9. 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 9 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, namely, port 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 9 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.

[0032] The second swing spool 22 is connected to the first hydraulic pump 9. 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 9 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 9 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.

[0033] 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.

[0034] [Bucket Spool] The bucket head-side spool 23 is connected to the second hydraulic pump 10. 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 10 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 10 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.

[0035] The bucket rod side spool 24 is connected to the second hydraulic pump 10. Explaining in more detail, the bucket rod side spool 24 is connected to the second main passage 32 via a bucket passage 51, and is further connected to the second hydraulic pump 10 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 10 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 and discharged from the rod-side port 7b of the bucket cylinder 7.

[0036] 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.

[0037] [Breaker Spool] The first breaker spool 25, which is an example of a first control spool, is connected to the first hydraulic pump 9. More specifically, the first breaker spool 25 is connected to the first main passage 31 via the first breaker passage 56 and further connected to the first hydraulic pump 9 via the first main passage 31. The first breaker spool 25 is also connected to the supply port 8a of the hydraulic breaker 8. The first breaker spool 25 controls the flow of hydraulic fluid supplied from the first hydraulic pump 9 to the supply port 8a of the hydraulic breaker 8. The hydraulic breaker 8 has two ports 8a and 8b, and the supply port 8a is one of the two ports 8a and 8b. The other port 8b, which is a discharge port 8b, is connected to the tank 30 via a pipe 59, and the hydraulic breaker 8 discharges hydraulic fluid from the discharge port 8b to the tank 30 via the pipe 59. In this embodiment, the first breaker spool 25 is connected to the supply port 8a via a supply passage 57. The first breaker spool 25 also has an unloading function. That is, the first breaker spool 25 is connected to the tank 30. More specifically, the first breaker spool 25 is connected to the tank 30 via a tank passage 33.

[0038] The first breaker spool 25 also strokes between a first supply position A1 and a first unload position A2. In this embodiment, the first breaker spool 25 is positioned at the first unload position A2 in a normal state and strokes from the first unload position A2 to the first supply position A1 via a first shutoff position A3. At the first supply position A1, the first main passage 31 is connected to the hydraulic breaker 8, and at the first unload position A2, the first main passage 31 is connected to the tank 30. At the first shutoff position A3, the first main passage 31 is shut off from both the hydraulic breaker 8 and the tank 30.

[0039] More specifically, the first breaker spool 25 receives pilot pressure output from each solenoid valve 25b in a direction resisting the biasing force of a spring mechanism 25d (described later in detail), and strokes to each of positions A1 to A3 in response to the pilot pressure of each solenoid valve 25b. At the first supply position A1, the first breaker spool 25 supplies hydraulic fluid from the first hydraulic pump 9 to the supply port 8a of the hydraulic breaker 8. At the first unload position A2, the first breaker spool 25 discharges hydraulic fluid flowing through the first main passage 31 to the tank 30. In other words, the first breaker spool 25 can fulfill both the supply function to the hydraulic breaker 8 and the unload function. The first breaker spool 25 adjusts its opening depending on the stroke. As a result, the first breaker spool 25 controls the flow rate of the hydraulic fluid supplied to the supply side port 8 a of the hydraulic breaker 8 and the flow rate of the hydraulic fluid discharged to the tank 30 .

[0040] The second breaker spool 26, which is an example of a second control spool, is connected to the second hydraulic pump 10. More specifically, the second breaker spool 26 is connected to the second main passage 32 via a second breaker passage 58 and further connected to the second hydraulic pump 10 via the second main passage 32. The second breaker spool 26 is also connected to the supply port 8a of the hydraulic breaker 8. The second breaker spool 26 controls the flow of hydraulic fluid supplied from the second hydraulic pump 10 to the supply port 8a of the hydraulic breaker 8. More specifically, the second breaker spool 26 is connected to the supply passage 57 in parallel with the first breaker spool 25 and is connected to the supply port 8a via the supply passage 57. The second breaker spool 26 also has an unloading function. That is, the second breaker spool 26 is connected to the tank 30. More specifically, the second breaker spool 26 is connected to the tank 30 via a tank passage 33 .

[0041] The second breaker spool 26 also strokes between a second supply position B1 and a second unload position B2. In this embodiment, the second breaker spool 26 is positioned at the second unload position B2 in a normal state and strokes from the second unload position B2 to the second supply position B1 via a second shutoff position B3. At the second supply position B1, the second main passage 32 is connected to the hydraulic breaker 8, and at the second unload position B2, the second main passage 32 is connected to the tank 30. At the second shutoff position B3, the second main passage 32 is shut off from both the hydraulic breaker 8 and the tank 30.

[0042] More specifically, the second breaker spool 26 receives pilot pressure output from each solenoid valve 26b in a direction resisting the biasing force of a spring mechanism 26d (described later in detail), and strokes to each of positions B1 to B3 in response to the pilot pressure of each solenoid valve 26b. At the second supply position B1, the second breaker spool 26 supplies hydraulic fluid from the second hydraulic pump 10 to the supply port 8a of the hydraulic breaker 8. At the second unload position B2, the second breaker spool 26 discharges hydraulic fluid flowing through the second main passage 32 to the tank 30. In other words, the second breaker spool 26 can fulfill both the supply function and the unload function for the hydraulic breaker 8. The second breaker spool 26 adjusts its opening according to the stroke. As a result, the second breaker spool 26 controls the flow rate of the hydraulic fluid supplied to the supply side port 8 a of the hydraulic breaker 8 and the flow rate of the hydraulic fluid discharged to the tank 30 .

[0043] [Converging Spool] The converging spool 27 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 27 receives pilot pressure output from the solenoid valve 27b 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 27b. The converging spool 27 opens and closes the converging passage 54 by stroking, and also adjusts the opening degree of the converging spool 27. In this way, the converging spool 27 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.

[0044] [Boom Regenerative Valve Body] The boom regenerative valve body 28 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 28 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 28 is connected to the head side passage 45 and the first arm passage 40. More specifically, the boom regenerative valve body 28 is connected to the head side passage 45 so as to be parallel to the spools 18, 19. Furthermore, the boom regenerative valve body 28 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 28 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 28 is a poppet-type valve element that opens and closes in response to the pilot pressure output from the solenoid valve 28a. The boom regenerative valve element 28 also adjusts its opening degree in response to the pilot pressure. As a result, the boom regenerative valve element 28 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.

[0045] <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 12-27, as described above. Furthermore, as shown in Figures 6 to 9, the multi-control valve 1 includes multiple spool covers 12c-27c, multiple spring mechanisms 12d-27d, and multiple solenoid valves 12a-24a, 12b-27b. 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.

[0046] 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 and 11c formed as follows.

[0047] As shown in FIGS. 3 and 4 , a plurality of spool holes 11b, 11c are formed on each of both height-wise side surfaces of the block body 11a. More specifically, a plurality of 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, eight spool holes 11b, 11c are formed on each height-wise side surface of the block body 11a. That is, eight first spool holes 11b are formed on one height-wise side surface of the block body 11a, and eight second spool holes 11c are formed on the other height-wise side surface. The spool holes 11b, 11c on each side surface are arranged in two rows in the width direction, which is an example of the row direction. Each row contains four spool holes 11b, 11c. In each row, the spool holes 11b, 11c are aligned in a row in the depth direction. In this embodiment, four spool holes 11b and four spool holes 11c are formed on each side surface of each block member 11d and 11e, and each of the spool holes 11b and 11c extends in the height direction from each side surface of the block body 11a in the height direction.

[0048] As shown in Figures 6 to 9, the spool holes 11b and 11c are arranged to correspond to each other. More specifically, the spool holes 11b and 11c are arranged to correspond to each other and extend toward the corresponding spool holes 11c and 11b. The pair of spool holes 11b and 11c, which are the corresponding spool holes 11b and 11c, are arranged in a line in the vertical direction. In this embodiment, the pair of spool holes 11b and 11c are aligned in the vertical direction 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 each other in the vertical direction so as to form a partition wall 11f between them.

[0049] The spools 12 to 27 are inserted into the valve block 11 as follows. That is, each of the spools 12 to 27 is slidably inserted into a corresponding spool hole 11b, 11c of the valve block 11. In this embodiment, each of the spools 16, 17, 20, 22, 24, 25, 26, and 27 is slidably inserted into the first spool hole 11b (see also FIG. 3). Each of the spools 16, 17, 20, 22, and 24 forms an inner pilot chamber 16e, 17e, 20e, 22e, and 24e on the bottom side of the first spool hole 11b (see also FIG. 4). 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").

[0050] In this embodiment, spools 26, 20, 17, and 24 are slidably inserted into the first spool holes 11b in the row on one side in the width direction, in order from one side in the depth direction. Spools 25, 27, 16, and 22 are slidably inserted into the first spool holes 11b in the row on the other side in the width direction, in order 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, in order 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, in order from one side in the depth direction. As a result, the first breaker spool 25 and the first traveling spool 12, and the second breaker spool 26 and the second traveling spool 13 are each lined up in a vertical row in combination and disposed on one side and the other side in the vertical direction. Furthermore, the boom rod side spool 20 and the first boom head side spool 18, and the junction spool 27 and the second boom head side spool 19 are also each lined up in a vertical row in combination and disposed on one side and the other side in the vertical direction. In addition, the second arm rod side spool 17 and the second arm head side spool 15, and the first arm rod side spool 16 and the first arm head side spool 14 are each lined up in a vertical row in combination and disposed on one side and the other side in the vertical direction. In addition, the bucket rod side spool 24 and bucket head side spool 23, and the respective combinations of the second swivel spool 22 and first swivel spool 21 are aligned in a row in the vertical direction and are respectively arranged on one side and the other side in the vertical direction.

[0051] The spool covers 12c to 27c are provided on the block body 11a so as to cover the openings of the respective spool holes 11b and 11c. That is, the spool covers 12c to 27c are provided on the block body 11a so as to cover the corresponding spools 12 to 27. More specifically, spool covers 16c, 17c, 20c, 22c, 24c, 25c, 26c, and 27c 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 27c are formed integrally with each other to form a double cover. However, the adjacent spool covers 12c to 27c do not necessarily have to be formed integrally with each other. Outer pilot chambers 12f to 27f are formed inside the spool covers 12c to 27c. The outer pilot chambers 12f to 27f correspond to the respective spools 12 to 27. Pilot pressure is introduced into the outer pilot chambers 12f to 27f, and the pilot pressure in each of the outer pilot chambers 12f to 24f acts on the corresponding spool 12 to 24 in a direction (hereinafter referred to as "axially inward") that resists the pilot pressure in the inner pilot chambers 12e to 24e.

[0052] The spring mechanisms 12d to 27d are housed in the spool covers 12c to 27c, respectively. In this embodiment, the spring mechanisms 12d to 27d are housed in the outer pilot chambers 12f to 27f, respectively. The spring mechanisms 12d to 27d correspond to the spools 12 to 27, and bias the corresponding spools 12 to 27. More specifically, the spring mechanisms 12d to 27d bias the spools 12 to 27 in the direction opposite to the stroke direction of the corresponding spools 12 to 27. This returns the spools 12 to 27 to their neutral positions.

[0053] 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.

[0054] The second solenoid valves 12b to 27b also correspond to the spools 12 to 27, respectively. The second solenoid valves 12b to 27b output pilot pressures corresponding to signals input to the corresponding spools 12 to 27. In this embodiment, the second solenoid valves 12b to 27b are attached to the spool covers 12c to 27c of the corresponding spools 12 to 27, and are connected to the outer pilot chambers 12f to 27f, respectively. The second solenoid valves 12b to 27b output pilot pressures to the corresponding outer pilot chambers 12f to 27f.

[0055] The pilot pressures output from the first solenoid valves 12a to 24a and second solenoid valves 12b to 27b configured in this manner act on the corresponding spools 12 to 27 in directions opposing each other. The biasing force of the spring mechanisms 12d to 27d also acts on the corresponding spools 12 to 27 in a direction opposing the pilot pressures from the first solenoid valves 12a to 24a and second solenoid valves 12b to 27b. Therefore, each spool 12 to 27 strokes to a position where the pilot pressures from the solenoid valves 12a to 24a and 12b to 27b and the biasing force of the spring mechanisms 12d to 27d are balanced. As a result, each spool 12 to 27 controls the flow of hydraulic fluid in accordance with the signals input to the solenoid valves 12a to 24a and 12b to 27b.

[0056] 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.

[0057] 6 , the first breaker passage 56 and the second breaker passage 58 are adjacent to the first breaker spool 25 and the second breaker spool 26, respectively, and are spaced apart on one and the other widthwise sides. The first breaker passage 56 is connected to the first main passage 31 and the first breaker spool 25, and the second breaker passage 58 is connected to the second main passage 32 and the second breaker spool 26. In each breaker spool 25, 26, the tank passage 33 is connected axially inward of the breaker passages 56, 58, and a supply passage 57 is connected axially outward of the breaker passages 56, 58. The supply passage 57 is connected to the supply side port 8a of the hydraulic breaker 8 via a breaker connection port 57a that opens on one depth-wise surface of the valve block 11.

[0058] The first and second running passages 34, 37 are adjacent to the first and second running spools 12, 13, respectively, and are spaced apart on one and the other widthwise sides. The first running passage 34 is connected to the first main passage 31 and the first running spool 12, and the second running passage 37 is connected to the second main passage 32 and the second running spool 13. In the first running spool 12, first and second supply and discharge passages 35, 36 are connected to both axial sides of the first running 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.

[0059] 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.

[0060] 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 27. The merging passage 54 connects the second main passage 32 and the first main passage 31 with the merging spool 27 interposed therebetween.

[0061] 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 28 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 .

[0062] 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 of the valve block 11 in the height direction. The rod-side passage 43 and the regeneration 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 across the two arm head-side spools 14, 15. The head-side passage 41 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 to the other side in the 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. The regeneration passage 55 extends from the second-arm rod-side spool 17 toward the head-side passage 41, with a check valve 51a interposed midway.

[0063] 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.

[0064] 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.

[0065] <Flow of Hydraulic Fluid in the Multi-Control Valve> In the multi-control valve 1, as described above, the breaker spools 25, 26 have an unloading function. More specifically, in the normal state, the breaker spools 25, 26 are located at unloading positions A2, B2 and discharge hydraulic fluid from the hydraulic pumps 9, 10 to the tank 30. This places the hydraulic pumps 9, 10 in an unloading state. Meanwhile, when driving the actuators 2-7, the breaker spools 25, 26 operate as follows. That is, pilot pressure is output from the solenoid valves 25b, 26b and directed to the outer pilot chambers 25f, 26f. This limits the flow rate of hydraulic fluid bled off from the hydraulic pumps 9, 10 to the tank 30 by the breaker spools 25, 26, allowing hydraulic fluid to be supplied to the actuators 2-7. Furthermore, the multi-control valve 1 operates as follows to drive the actuators 2-8.

[0066] 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 introduced into 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 9 to the first traveling motor 2 via the first traveling spool 12, and from the hydraulic pump 10 to the second traveling motor 3 via the second traveling spool 13. This drives the traveling device.

[0067] 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 actuated. At this time, hydraulic fluid is supplied from the hydraulic pump 9 to the first supply / discharge port 4a via the first swing spool 21, and further discharged from the second supply / discharge port 4b via the second swing spool 22 to the tank 30. The first swing spool 21 and the second swing spool 22 can stroke independently, and their respective openings can be adjusted independently.

[0068] 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 chambers 14f and 17e. As a result, hydraulic fluid from the first hydraulic pump 9 is led 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 regenerated from the second arm rod side spool 17 to the head side port 6a via the regeneration passage 55. This leads to the extension of the arm cylinder 6. Furthermore, when pilot pressure is also output from the solenoid valve 15b, the pilot pressure is led to the pilot chamber 15f. This allows hydraulic fluid from the second hydraulic pump 10 to also be led to the head side port 6a of the arm cylinder 6 via the second arm head side spool 15. This allows a greater flow 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, discharging 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 to 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 directs pilot pressure to the pilot chambers 14e and 16f, causing the arm cylinder 6 to retract. Furthermore, the output of pilot pressure from the solenoid valves 15a and 17b allows a larger flow rate of hydraulic fluid to flow to the rod-side port 6b of the arm cylinder 6. Note that the spools 14 to 17 can stroke independently of each other, and their respective openings can be adjusted independently of each other. Therefore, the multi-control valve 1 can also independently control the flow rates supplied to and discharged from the head-side port 6a and the rod-side port 6b.

[0069] 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 10 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 9 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 be supplied 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. This causes pilot pressure to be introduced into pilot chambers 18e, 20f, causing the boom cylinder 5 to retract. Note that each spool 18-20 can stroke independently of the others, and their respective openings can be adjusted independently of the others. 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.

[0070] 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.

[0071] Furthermore, when activating the hydraulic breaker 8, the multi-control valve 1 operates as follows. That is, pilot pressure is output from the solenoid valves 25b, 26b and directed to the outer pilot chambers 25f, 26f. When the pilot pressure of the solenoid valves 25b, 26b rises to the operating pressure, the breaker spools 25, 26 stroke to the supply positions A1, B1, respectively. This causes hydraulic fluid to be supplied to the hydraulic breaker 8 from the hydraulic pumps 9, 10 via the breaker spools 25, 26. This drives the hydraulic breaker 8. Note that when activating the hydraulic breaker 8, it is not necessary for both breaker spools 25, 26 to operate; it is sufficient for at least one of them to operate.

[0072] For example, while one breaker spool 25 is stroked to the first supply position A1, the opening degree of the other breaker spool 26 may be controlled at the second unload position B2. In this case, the hydraulic fluid flowing through the second main passage 32 can be bled off to the tank 30. This makes it possible to control the flow rate of the hydraulic fluid flowing through the second main passage 32. Furthermore, while the opening degree of the other breaker spool 26 is controlled at the second unload position B2, the merging passage 54 may be opened by the merging spool 27 to merge the two main passages 31, 32. This makes it possible to bleed off not only the hydraulic fluid in the second main passage 32 but also the hydraulic fluid merged from the first main passage 31 to the tank 30.

[0073] 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 28a. 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 28. 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.

[0074] 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 27. This connects the first hydraulic pump 9 and the second hydraulic pump 10. 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.

[0075] In the multi-control valve 1 of this embodiment, the first breaker spool 25 is connected to the tank 30 and strokes between a first supply position A1 and a first unload position A2. Therefore, the first breaker spool 25 can have both a supply function and an unload function. This allows the number of spools 12 to 26 provided in the multi-control valve 1 to be reduced, thereby preventing the multi-control valve 1 from becoming larger.

[0076] Furthermore, in the multi-control valve 1 of this embodiment, the first breaker spool 25 strokes to the first shutoff position A3. Therefore, the first breaker spool 25 can stop both the supply function and the unloading function. This eliminates the need to provide a new valve to stop both the supply function and the unloading function, and prevents an increase in the number of parts in the multi-control valve 1.

[0077] Furthermore, in the multi-control valve 1 of this embodiment, the second breaker spool 26 is connected to the second main passage 32 and the tank 30, and strokes between the second supply position B1 and the second unload position B2, respectively. Therefore, the second breaker spool 26 also has both a supply function and an unload function. This allows the number of spools 12 to 26 provided in the multi-control valve 1 to be reduced, thereby preventing the multi-control valve 1 from becoming larger. In addition, since hydraulic fluid can be sent to the hydraulic breaker 8 from two hydraulic pumps 9 and 10, a larger amount of hydraulic fluid can be sent to the hydraulic breaker 8.

[0078] Furthermore, in the multi-control valve 1 of this embodiment, the second breaker spool 26 strokes to the second shutoff position B3. Therefore, the second breaker spool 26 can stop both the supply function and the unloading function. This eliminates the need to provide a new valve to stop both the supply function and the unloading function, and prevents an increase in the number of parts in the multi-control valve 1.

[0079] Furthermore, in the multi-control valve 1 of this embodiment, the merging spool 27 is provided in the valve block 11 and opens and closes the merging passage 54. Therefore, by opening the merging passage 54 with the merging spool 27, the two main passages 31, 32 can be connected via the merging passage 54. This makes it possible to supply hydraulic fluid to the hydraulic breaker 8 from one of the two breaker spools 25, 26 while bleeding the hydraulic fluid into the tank 30 from the other.

[0080] Furthermore, in the multi-control valve 1 of this embodiment, the first and second breaker spools 25, 26 supply hydraulic fluid to a hydraulic breaker 8 that is different from the boom cylinder 5, arm cylinder 6, bucket cylinder 7, travel motors 2, 3, and swing motor 4. Therefore, bleed-off control can be performed by the first and second breaker spools 25, 26 for the boom cylinder 5, arm cylinder 6, bucket cylinder 7, travel motors 2, 3, and swing motor 4. This makes it possible to mitigate impacts when the boom cylinder 5, arm cylinder 6, bucket cylinder 7, travel motors 2, 3, and swing motor 4 are operated.

[0081] Furthermore, in the multi-control valve 1 of this embodiment, controllability is ensured by meter-in control of the flow rate of the hydraulic fluid supplied to the hydraulic breaker 8. Therefore, it is easy to make the first and second breaker spools 25, 26 serve as both an unloading function.

[0082] Furthermore, in the multi-control valve 1 of this embodiment, the spools 12 to 26, including the first and second breaker spools 25, 26, are inserted into the valve block 11 so as to be slidable in the first direction. Therefore, the spools 12 to 26 are arranged in the valve block 11 so as to extend in the first direction. This prevents the valve block 11 from becoming too large.

[0083] Furthermore, in the multi-control valve 1 of the present embodiment, the bucket head-side spool 23 and the bucket rod-side spool 24 are arranged in the valve block 11 aligned in the first direction relative to the swing spools 21, 22, respectively. Furthermore, the first and second breaker spools 25, 26 are arranged in the valve block 11 aligned in the first direction relative to the traveling spools 12, 13, respectively. Because the multiple spools 12, 13, 21 to 26 are arranged in the first direction relative to the valve block 11, an increase in size can be further suppressed.

[0084] [Other Embodiments] In the multi-control valve 1 of this embodiment, the hydraulic breaker 8 is cited as an example of the first hydraulic actuator, but the first hydraulic cylinder may be another hydraulic actuator. The first hydraulic actuator is, for example, an optional actuator. Explaining in more detail, the first hydraulic actuator is preferably an optional actuator that is primarily subjected to meter-in control, such as a hydraulic cutter or hydraulic drill, other than the actuators 2 to 8 described above. In other words, the first hydraulic actuator is preferably one that does not require meter-out control.

[0085] Furthermore, in the multi-control valve 1 of this embodiment, the breaker spools 25, 26 are connected to the main passages 31, 32, respectively, but the breaker spool 25 may be connected to only one of the main passages 31, 32. In this case, an unloading spool may be connected to the other of the main passages 31, 32. Furthermore, by providing the confluence spool 27 in the multi-control valve 1, the aforementioned unloading spool is not necessarily required. Furthermore, the multi-control valve 1 does not necessarily need to be provided with the confluence spool 27, nor does it necessarily need to have a regenerative function or a regenerative function.

[0086] Furthermore, although the breaker spools 25, 26 in the multi-control valve 1 of this embodiment are positioned at the unload positions A2, B2 in the normal state, they may also be positioned at the cut-off positions A3, B3 in the normal state.

[0087] The number and shape of the spool holes 11b, 11c and the arrangement of the spools 12 to 27 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.

[0088] <Exemplary Embodiment> A multi-control valve in a first aspect controls the flow of hydraulic fluid to a first hydraulic actuator and includes a valve block including a first main passage connected to a first hydraulic pump, and a first control spool provided in the valve block and controlling the flow rate of hydraulic fluid flowing to the first hydraulic actuator, the first control spool stroking between a first supply position connecting the first main passage to the first hydraulic actuator and a first unload position connecting the first main passage to the tank.

[0089] According to the above aspect, the first control spool is connected to the tank and strokes between a first supply position and a first unload position. Therefore, the first control spool can have both a supply function and an unload function. This allows the number of control spools included in the multi-control valve to be reduced, thereby preventing the multi-control valve from becoming too large.

[0090] In a second aspect, the multi-control valve is the multi-control valve of the first aspect, wherein the first control spool strokes to a blocking position that blocks communication between the first hydraulic actuator and the first main passage and between the first hydraulic actuator and the tank and between the first control spool and the first main passage and the first control spool.

[0091] According to the above aspect, the first control spool strokes to the first shutoff position. Therefore, the first control spool can stop both the supply function and the unloading function. This eliminates the need to provide a new valve to stop both the supply function and the unloading function, and prevents an increase in the number of parts in the multi-control valve.

[0092] A multi-control valve in a third aspect is the multi-control valve of the first or second aspect, further comprising a second control spool provided in the valve block and controlling the flow rate of hydraulic fluid flowing to the first hydraulic actuator, the valve block including a second main passage connected to a second hydraulic pump, and the second control spool strokes between a second supply position connecting the second main passage to the first hydraulic actuator and a second unload position connecting the second main passage to the tank.

[0093] According to the above aspect, the second control spool is connected to the second main passage and the tank and strokes between a second supply position and a second unload position. Therefore, the second control spool also has both a supply function and an unload function. This allows the number of control spools included in the multi-control valve to be reduced, thereby preventing the multi-control valve from becoming larger. Furthermore, since hydraulic fluid can be supplied from two hydraulic pumps to the first hydraulic actuator, a larger amount of hydraulic fluid can be supplied to the first hydraulic actuator.

[0094] In a multi-control valve according to a fourth aspect, in the multi-control valve according to the third aspect, the second control spool is stroked to a blocking position where it blocks communication between the first hydraulic actuator and the second main passage and communication between the tank and the second main passage.

[0095] According to the above aspect, the second control spool strokes to the second shutoff position. Therefore, the second control spool can stop both the supply function and the unloading function. This eliminates the need to provide a new valve to stop both the supply function and the unloading function, and prevents an increase in the number of parts in the multi-control valve.

[0096] A multi-control valve in a fifth aspect is the multi-control valve of the third or fourth aspect, further comprising a confluence spool, wherein the valve block further includes a confluence passage connecting the first and second main passages, and the confluence spool is provided in the valve block and opens and closes the confluence passage.

[0097] According to the above aspect, the confluence spool is provided in the valve block and opens and closes the confluence passage. Therefore, by opening the confluence passage with the confluence spool, the two main passages can be connected via the confluence passage. This allows one of the two control spools to supply hydraulic fluid to the first hydraulic actuator while the other spool bleeds hydraulic fluid to the tank.

[0098] The multi-control valve in a sixth aspect is the multi-control valve of any one of the third to fifth aspects, further comprising: a boom control spool provided in the valve block to control the flow of hydraulic fluid supplied to and discharged from a boom cylinder; an arm control spool provided in the valve block to control the flow of hydraulic fluid supplied to and discharged from an arm cylinder; a bucket control spool provided in the valve block to control the flow of hydraulic fluid supplied to and discharged from a bucket cylinder; a swing control spool provided in the valve block to control the flow of hydraulic fluid supplied to and discharged from a swing motor; and a travel control spool provided in the valve block to control the flow of hydraulic fluid supplied to and discharged from a travel motor, and the first and second control spools supply hydraulic fluid to the boom cylinder, the arm cylinder, the bucket cylinder, the travel motor, and the first hydraulic actuator different from the swing motor.

[0099] According to the above aspect, the first and second control spools supply hydraulic fluid to a first hydraulic actuator that is different from the boom cylinder, the arm cylinder, the bucket cylinder, the travel motor, and the swing motor. Therefore, bleed-off control can be performed by the first control spool for the boom cylinder, the arm cylinder, the bucket cylinder, the travel motor, and the swing motor. This makes it possible to reduce shocks that occur when the boom cylinder, the arm cylinder, the bucket cylinder, the travel motor, and the swing motor are operated.

[0100] In a seventh aspect of the multi-control valve, in the multi-control valve of the sixth aspect, the first hydraulic actuator is a hydraulic breaker, each of the first control spools controls the degree of opening between the first main passage and the hydraulic breaker, and each of the second control spools controls the degree of opening between the second main passage and the hydraulic breaker.

[0101] According to the above aspect, the first hydraulic actuator is a hydraulic breaker. In a hydraulic breaker, controllability is ensured by meter-in control of the flow rate of hydraulic fluid supplied thereto. Therefore, it is easy to make the first and second control spools serve as both an unloading function.

[0102] A multi-control valve in an eighth aspect is the multi-control valve of the seventh aspect, wherein the boom control spool, the arm control spool, the bucket control spool, the swing control spool, and the traveling control spool are inserted into the valve block so as to be slidable in a first direction, and the first and second control spools are inserted into the valve block so as to be slidable in the first direction.

[0103] According to the above aspect, the control spools, including the first and second control spools, are inserted into the valve block so as to be slidable in the first direction. Therefore, the control spools are arranged in the valve block so as to extend in the first direction. This prevents the valve block from becoming large.

[0104] A multi-control valve in a ninth aspect is the multi-control valve of the eighth aspect, wherein the valve block is provided with a pair of travel control spools, the bucket control spools are arranged in the valve block aligned with each other in a first direction relative to the swing control spool, and the first and second control spools are arranged in the valve block aligned with each other in the first direction relative to each of the pair of travel control spools.

[0105] According to the above aspect, the bucket control spool is arranged in the valve block aligned with the swing control spool in the first direction. Also, the first and second control spools are arranged in the valve block aligned with each other in the first direction with respect to each of the pair of control spools. Since the multiple control spools are arranged in the first direction, it is possible to further prevent the size of the valve block from increasing.

[0106] 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 a first hydraulic actuator, comprising: a valve block including a first main passage connected to a first hydraulic pump; and a first control spool provided in the valve block that controls the flow rate of hydraulic fluid flowing to the first hydraulic actuator, wherein the first control spool strokes between a first supply position that connects the first main passage to the first hydraulic actuator and a first unload position that connects the first main passage to a tank.

2. The multi-control valve according to claim 1, wherein the first control spool strokes to a blocking position that blocks communication between the first hydraulic actuator and the tank and the first main passage.

3. A multi-control valve as claimed in claim 1, further comprising a second control spool provided in said valve block for controlling the flow rate of hydraulic fluid flowing to said first hydraulic actuator, said valve block including a second main passage connected to a second hydraulic pump, said second control spool stroking between a second supply position connecting said second main passage to said first hydraulic actuator and a second unload position connecting said second main passage to said tank.

4. The multi-control valve according to claim 3, wherein the second control spool strokes to a blocking position that blocks communication between the first hydraulic actuator and the tank and the second main passage.

5. The multi-control valve according to claim 3, further comprising a confluence spool, wherein the valve block further includes a confluence passage connecting the first and second main passages, and the confluence spool is provided in the valve block and opens and closes the confluence passage.

6. The multi-control valve according to claim 3, further comprising: a boom control spool provided in the valve block and controlling the flow of hydraulic fluid supplied to and discharged from a boom cylinder; an arm control spool provided in the valve block and controlling the flow of hydraulic fluid supplied to and discharged from an arm cylinder; a bucket control spool provided in the valve block and controlling the flow of hydraulic fluid supplied to and discharged from a bucket cylinder; a swing control spool provided in the valve block and controlling the flow of hydraulic fluid supplied to and discharged from a swing motor; and a travel control spool provided in the valve block and controlling the flow of hydraulic fluid supplied to and discharged from a travel motor, wherein the first and second control spools supply hydraulic fluid to the boom cylinder, the arm cylinder, the bucket cylinder, the travel motor, and the first hydraulic actuator different from the swing motor.

7. A multi-control valve as described in claim 6, wherein the first hydraulic actuator is a hydraulic breaker, each of the first control spools controls the degree of opening between the first main passage and the hydraulic breaker, and each of the second control spools controls the degree of opening between the second main passage and the hydraulic breaker.

8. A multi-control valve as described in claim 7, wherein the boom control spool, the arm control spool, the bucket control spool, the swing control spool, and the traveling control spool are inserted into the valve block so as to be slidable in a first direction, and the first and second control spools are inserted into the valve block so as to be slidable in the first direction.

9. The multi-control valve described in claim 88, wherein the valve block is provided with a pair of travel control spools, the bucket control spools are arranged in the valve block adjacent to each other in a first direction relative to the swing control spool, and the first and second control spools are arranged in the valve block adjacent to each other in the first direction relative to each of the pair of travel control spools.

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