Multi-control valve

Abstract

This multi-control valve comprises: a valve block including a plurality of spool holes; a plurality of spools that are inserted into the plurality of spool holes, respectively, so as to be able to stroke, and that control a flow of working fluid by stroking; a spool cover group including a plurality of pieces of a spool cover for blocking the plurality of spool holes; and a solenoid valve group that includes a plurality of pairs of solenoid valves corresponding to the plurality of spools, respectively, and that includes a plurality of pairs of solenoid valves, each pair outputting pilot pressures to the corresponding spool in such directions that the pilot pressures act against each other. Each pair of solenoid valves is provided in the corresponding spool cover.

Description

Multi-Control Valve

[0001] The present disclosure relates to a multi-control valve having multiple spools.

[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 actuators. One example of a hydraulic drive device is the hydraulic drive system disclosed in Patent Document 1. The hydraulic drive system of Patent Document 1 is provided with a meter-in control valve and a meter-out control valve, which control the meter-in flow rate and meter-out flow rate of the hydraulic actuators.

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

[0004] The hydraulic drive system of Patent Document 1 is realized, for example, by a multi-control valve. The multi-control valve is provided with multiple spools that constitute meter-in control valves and meter-out control valves. The multi-control valve is configured to be able to supply hydraulic fluid to multiple hydraulic actuators, such as a boom cylinder, an arm cylinder, a bucket cylinder, and a swing motor. The multi-control valve is configured to be able to control the meter-in flow rate and the meter-out flow rate for each hydraulic actuator. Therefore, the multi-control valve is provided with many spools, and each spool has many parts. Therefore, the multi-control valve has a large number of parts.

[0005] Therefore, an object of the present disclosure is to provide a multi-control valve that can reduce the number of parts.

[0006] The multi-control valve of the present disclosure comprises a valve block including a plurality of spool holes, a plurality of spools that are stroably inserted into the plurality of spool holes and control the flow of hydraulic fluid by stroking, a spool cover group including a plurality of spool covers that cover the plurality of spool holes, and a solenoid valve group including a plurality of pairs of solenoid valves corresponding to each of the plurality of spools, each pair outputting pilot pressures that act in directions opposing each other to the corresponding spool, and the pair of solenoid valves are provided on the corresponding spool covers.

[0007] According to the present disclosure, the spool cover covers multiple spool holes. This reduces the number of covers that are placed over the spool, thereby reducing the number of parts in the multi-control valve. Furthermore, multiple pairs of solenoid valves are provided on the spool cover. This allows for a compact layout of the solenoid valves.

[0008] According to the multi-control valve of the present disclosure, the number of parts can be reduced.

[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] 1 is a plan view of a multi-control valve provided in a hydraulic drive device according to the present disclosure, as seen from one side in the height direction. FIG. 2 is a circuit diagram showing a hydraulic circuit formed in the multi-control valve. FIG. 3 is a bottom view of the multi-control valve of FIG. 1, as seen from the other side in the height direction. FIG. 4 is a cross-sectional view of the multi-control valve of FIG. 1, taken along section line IV-IV. FIG. 5 is an enlarged cross-sectional view of the dual cover of the multi-control valve of FIG. 4. FIG. 6 is an enlarged cross-sectional view of the spool cover of FIG. 5, taken along section line VI-VI. FIG. 7 is a cross-sectional view of the multi-control valve of FIG. 6, taken along section line VII-VII.

[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 provided with multiple actuators 2 to 8 as shown in FIG. 2. In this embodiment, the shovel is provided with a first traveling motor 2, a second traveling motor 3, a swing motor 4, a boom cylinder 5, an arm cylinder 6, a bucket cylinder 7, and a hydraulic breaker 8. However, the shovel may be provided with actuators other than the seven described above, or may not be provided with the hydraulic breaker 8. Furthermore, the construction machine may 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, which is 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] 1 and 3, the multi-control valve 1 configured as above includes a valve block 11, a plurality of spools 12 to 27, and a plurality of spool covers 61 to 64, which will be described in detail later. In this embodiment, the multi-control valve 1 includes 16 spools 12 to 27. Note that 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] The valve block 11 is formed, for example, in the shape of a rectangular parallelepiped. Two hydraulic pumps 9, 10 are connected to the valve block 11, and hydraulic fluid is supplied from the two hydraulic pumps 9, 10. The spools 12-26 are each inserted into the valve block 11 so as to be able to move. In this embodiment, the spools 12-26 are inserted into the valve block 11 so as to be able to move in the height direction, which is an example of a first direction. The spools 12-26 also control the flow of hydraulic fluid by stroking. More specifically, each of the spools 12-26 is associated with a respective actuator 2-8, and controls the flow of hydraulic fluid supplied to or discharged from the corresponding actuator 2-8. 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 swivel spool 21, a second swivel 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. In addition to the spools 12 to 26, a junction spool 27 is inserted into the valve block 11 so as to be movable in the height direction.

[0016] 1 and 3, the multi-control valve 1 also includes solenoid valve groups 29U and 29L. The solenoid valve groups 29U and 29L are respectively arranged on one and the other sides in the height direction of the multi-control valve 1. The solenoid valve group 29U includes a plurality of pairs of solenoid valves (five pairs of solenoid valves in this embodiment) 16a, 16b, 17a, 17b, 20a, 20b, 22a, 22b, 24a, and 24b. The solenoid valve group 29L also includes a plurality of pairs of solenoid valves (eight pairs of solenoid valves in this embodiment) 12a, 12b, 13a, 13b, 14a, 14b, 15a, 15b, 18a, 18b, 19a, 19b, 21a, 21b, 23a, and 23b. More specifically, the solenoid valve group 29U includes first solenoid valves 16a, 17a, 20a, 22a, and 24a and second solenoid valves 16b, 17b, 20b, 22b, and 24b to 27b, as shown in FIG. 1. The solenoid valve group 29L includes first solenoid valves 12a to 15a, 18a, 19a, 21a, and 23a and second solenoid valves 12b to 15b, 18b, 19b, 21b, and 23b, as shown in FIG. 3. The solenoid valves 12a to 24a and 12b to 27b correspond to the spools 12 to 27, respectively. The solenoid valves 12a to 24a and 12b to 27b output pilot pressures to the corresponding spools 12 to 27 in response to input signals. As a result, each of the solenoid valves 12a to 24a and 12b to 27b strokes the corresponding spool 12 to 27. Explaining in more detail, each of the pairs of solenoid valves 12a to 24a and 12b to 24b outputs pilot pressures that act in opposing directions on the corresponding spool 12 to 24. For example, the pair of solenoid valves 17a and 17b outputs pilot pressures that act in opposing directions on the spool 17. The multi-control valve 1 configured in this manner has a hydraulic circuit 1a as follows:

[0017] <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. The first main passage 31 is connected to the first hydraulic pump 9, and the second main passage 32 is connected to the second hydraulic pump 10. The first main passage 31 is connected to spools 12, 14, 16, 19, 21, 22, and 25 in parallel. The second main passage 32 is connected to spools 13, 15, 17, 18, 20, 23, 24, and 26 in parallel. The tank passage 33 is connected to the tank 30. Each of the spools 12 to 27 will be described in more detail below.

[0018] [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.

[0019] 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.

[0020] [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.

[0021] 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.

[0022] 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.

[0023] 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 regenerates hydraulic fluid discharged from the rod side port 6b of the arm cylinder 6 to the head side port 6a. More specifically, the second-arm rod-side spool 17 is connected in parallel to the first-arm rod-side spool 16 in the rod-side passage 43. The second-arm rod-side spool 17 is connected to the rod-side port 6b via the rod-side passage 43. A regeneration passage 55 having a check valve 55a therein is also connected to the second-arm rod-side spool 17. The regeneration passage 55 is connected to the head-side port 6a, and hydraulic fluid discharged from the rod-side port 6b is regenerated to the head-side port 6a via the regeneration passage 55. In this embodiment, the regeneration passage 55 is connected to the head-side passage 41, and is connected to the head-side port 6a via the head-side passage 41.

[0024] 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 to either the second main passage 32 or 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 the flow rate of hydraulic fluid regenerated to the head-side port 6a.

[0025] 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.

[0026] [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.

[0027] 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.

[0028] 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.

[0029] 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.

[0030] [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.

[0031] 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.

[0032] 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.

[0033] [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.

[0034] 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.

[0035] 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.

[0036] [Breaker Spool] The first breaker spool 25 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-side 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. That is, the first breaker spool 25 unloads the hydraulic fluid in the first main passage 31 to the tank 30 by switching the connection of the first main passage 31 from the hydraulic breaker 8 to the tank 30. Furthermore, the first breaker spool 25 cuts off communication between the first main passage 31 and each of the hydraulic breaker 8 and the tank 30.

[0037] 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) and strokes in response to the pilot pressure of each solenoid valve 25b. In its normal state, the first breaker spool 25 connects the first main passage 31 to the tank 30, and by stroking, it blocks the first main passage 31. Furthermore, by further stroking, the first breaker spool 25 further connects the first main passage 31 to the hydraulic breaker 8. The first breaker spool 25 adjusts its opening in response to the stroke amount. As a result, the first breaker spool 25 controls the flow rate of hydraulic fluid supplied to the supply port 8a of the hydraulic breaker 8 and the flow rate of hydraulic fluid discharged to the tank 30.

[0038] The second breaker spool 26 is connected to the second hydraulic pump 10. More specifically, the second breaker spool 26 is connected to the second main passage 32 via the second breaker passage 58 and further connected to the second hydraulic pump 10 via the second main passage 32. Similarly to the first breaker spool 25, the second breaker spool 26 is connected to the supply port 8a of the hydraulic breaker 8 and 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 the tank passage 33. That is, the second breaker spool 26 unloads the hydraulic fluid in the second main passage 32 to the tank 30 by switching the connection destination of the second main passage 32 from the hydraulic breaker 8 to the tank 30. Furthermore, the first breaker spool 25 cuts off communication between the second main passage 32 and each of the hydraulic breaker 8 and the tank 30.

[0039] 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), and strokes in response to the pilot pressure of each solenoid valve 26b. In its normal state, the second breaker spool 26 connects the first main passage 31 to the tank 30, and by stroke, it blocks the first main passage 31. Furthermore, by further stroke, the second breaker spool 26 connects the second main passage 32 to the hydraulic boule 8. The second breaker spool 26 adjusts its opening in response to the stroke amount. As a result, the second breaker spool 26 controls the flow rate of hydraulic fluid supplied to the supply port 8a of the hydraulic breaker 8 and the flow rate of hydraulic fluid discharged to the tank 30.

[0040] [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.

[0041] [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 opens and closes at an opening degree according to the pilot pressure output from the solenoid valve 28 a, thereby regenerating hydraulic fluid from the head side port 5 a of the boom cylinder 5 to the head side port 6 a or the rod side port 6 b of the arm cylinder 6, and can also control the regenerated flow rate.

[0042] <Specific Configuration of Multi-Control Valve> The specific configuration of the multi-control valve 1 will be described below. As shown in Figures 1 and 3, the multi-control valve 1 includes a valve block 11 and multiple spools 12-27, as described above. The multi-control valve 1 also includes multiple spool cover groups 60U, 60L, multiple spring mechanisms 12d-27d, and the aforementioned multiple solenoid valve groups 29U, 29L (see Figure 4). The valve block 11 also includes a block body 11a and multiple spool holes 11b, 11c.

[0043] As shown in FIGS. 1 and 3, the block body 11a is formed, for example, in a substantially 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 depth direction, which is an example of the second direction, is a direction that intersects with the height direction and is a direction perpendicular to the height direction in this embodiment. The block body 11a has multiple spool holes 11b and 11c formed as follows.

[0044] As shown in FIG. 4 , the multiple spool holes 11b, 11c are bottomed holes extending in the height direction. The multiple spool holes 11b, 11c are formed on both height-direction side surfaces of the block body 11a. More specifically, the multiple spool holes 11b, 11c are arranged in two rows on each height-direction side surface of the block body 11a (see FIGS. 1 and 3 ). In this embodiment, for example, eight spool holes 11b, 11c are formed on each height-direction side surface of the block body 11a. That is, eight first spool holes 11b are formed on one height-direction end surface of the block body 11a, and eight second spool holes 11c are formed on the other height-direction end surface. The spool holes 11b, 11c on each side surface are arranged in two rows in the width direction. The width direction, which is an example of a third direction, is a direction intersecting the height direction and the depth direction, and in this embodiment, is a direction perpendicular to the height direction and the depth direction. Each row has four spool holes 11b, 11c. In each row, the spool holes 11b, 11c are aligned in a line in the depth direction. In this embodiment, four spool holes 11b, 11c are formed on each side surface of each of the block members 11d, 11e. Each of the spool holes 11b, 11c extends in the height direction from each side surface of the block body 11a in the height direction.

[0045] The spool holes 11b, 11c are arranged to correspond to each other as shown in FIG. 4. More specifically, the spool holes 11b, 11c are arranged to correspond to each other and extend toward the corresponding spool holes 11c, 11b. A pair of corresponding spool holes 11b, 11c are arranged in a line in the vertical direction with their bottoms butting against each other. In this embodiment, the pair of spool holes 11b, 11c are arranged in a line in the vertical direction with their axes aligned. The pair of spool holes 11b, 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.

[0046] 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 or 11c of the valve block 11. In this embodiment, each of the spools 16, 17, 20, 22, 24, and 25 to 27 is slidably, i.e., strokeably, inserted into the first spool hole 11b (see FIG. 1). The spools 16, 17, 20, 22, and 24 define inner pilot chambers 16e, 17e, 20e, 22e, and 24e at the bottom of the first spool hole 11b (see FIG. 4). That is, the first spool hole 11b includes the inner pilot chambers 16e, 17e, 20e, 22e, and 24e defined by the spools 16, 17, 20, 22, and 24, respectively. The spools 12 to 15, 18, 19, 21, and 23 are slidably inserted into the second spool bore 11c. The spools 12 to 15, 18, 19, 21, and 23 define inner pilot chambers 12e to 15e, 18e, 19e, 21e, and 23e on the bottom side of the second spool bore 11c. In other words, the second spool bore 11c includes inner pilot chambers 12e to 15e, 18e, 19e, 21e, and 23e defined by the spools 12 to 15, 18, 19, 21, and 23, respectively. For ease of explanation, only inner pilot chambers 13e, 15e, 17e, 18e, 20e, 23e, and 24e are shown in the figure, and the remaining inner pilot chambers are omitted. As will be described in detail later, pilot pressure is guided to each of the inner pilot chambers 12e to 24e from the first solenoid valves 12a to 24a, and each of the spools 12 to 24 receives the pilot pressure of the inner pilot chambers 12e to 24e in the direction toward the opening of each spool hole 11b, 11c (hereinafter referred to as "axially outward").

[0047] In this embodiment, as shown in Fig. 1, 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. On the other hand, as shown in Fig. 3, 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.

[0048] As shown in FIG. 4, each of the spool cover groups 60U, 60L is provided on one end surface and the other end surface of the block main body 11a in the height direction. Each of the spool cover groups 60U, 60L includes a plurality of first spool covers 61-64 and second spool covers 65-68. In this embodiment, each of the spool cover groups 60U, 60L includes four first spool covers 61-64 and four second spool covers 65-68. That is, the first spool covers 61-64 are provided on one end surface of the valve block 11 in the height direction, and the second spool covers 65-68 are provided on the other end surface of the valve block 11 in the height direction. Each of the first spool covers 61-64 is provided on the block body 11a so as to cover a plurality of first spool holes 11b, and each of the second spool covers 65-68 is provided on the block body 11a so as to cover a plurality of second spool holes 11c. In this embodiment, each of the first spool covers 61-64 is provided on one end face in the height direction of the block body 11a so as to cover two adjacent first spool holes 11b. Each of the second spool covers 65-68 is provided on the other end face in the height direction of the block body 11a so as to cover two adjacent second spool holes 11c.

[0049] More specifically, the first spool covers 61 to 64 close the first spool holes 11b (i.e., the corresponding spool holes 11b) into which the corresponding pairs of spools 26 and 20, spools 25 and 27, spools 17 and 24, and spools 16 and 22 are inserted. That is, the first spool covers 61 to 64 cover the corresponding pairs of spools 20 and 26, spools 25 and 27, spools 17 and 24, and spools 16 and 22, respectively. Furthermore, the second spool covers 65 to 68 close the second spool holes 11c (i.e., the corresponding spool holes 11c) into which the corresponding pairs of spools 13 and 18, spools 12 and 19, spools 15 and 23, and spools 14 and 21 are inserted, respectively. That is, the second spool covers 65 to 68 are placed over the corresponding pairs of spools 12 and 19, 13 and 18, 14 and 21, and 15 and 23, respectively.

[0050] The spool covers 61 to 68 arranged in this manner extend in the height direction as shown in Figure 4, and are formed into a rectangular parallelepiped shape that is horizontally elongated in the depth direction as shown in Figures 1 and 3. Each of the spool covers 61 to 68 has a mounting flange 60a at one end in the height direction. As shown in Figure 4, the spool covers 61 to 68 are attached to the valve block 11 by abutting the mounting flange 60a against each side surface of the valve block 11 in the height direction and fastening the mounting flange 60a to the valve block 11.

[0051] Each of the spool covers 61 to 68 also includes an outer pilot chamber 12f to 27f. As with the inner pilot chambers 12e to 24e, for the sake of convenience, only the outer pilot chambers 13f, 15f, 17f, 18f, 20f, 23f, and 24f of the outer pilot chambers 12f to 27f are illustrated, and the remaining ones are omitted. The same applies to the spring mechanisms 12d to 27d described below. The outer pilot chambers 12f to 27f correspond to each of the spools 12 to 27. In this embodiment, each of the outer pilot chambers 12f to 27f is formed from the spool cover 61 to 68 to the valve block 11. More specifically, each of the spool covers 61 to 68 has a top hole that connects to each of the spool holes 11b and 11c. Each of the outer pilot chambers 12f to 27f is defined by its top hole, the spool holes 11b and 11c connected to the top hole, and the spools 12 to 27 inserted therein. In this embodiment, as can be seen from the above description, only a portion of the outer pilot chambers 12f to 27f is formed in the spool covers 61 to 68, but all of the outer pilot chambers 12f to 27f may be formed therein.

[0052] Furthermore, as will be described in detail later, the pilot pressures of the second solenoid valves 12b to 27b are introduced into the outer pilot chambers 12f to 27f. Therefore, the pilot pressures of the second solenoid valves 12b to 27b act axially inward on the corresponding spools 12 to 27. As a result, the pilot pressures of the outer pilot chambers 12f to 24f act on the corresponding spools 12 to 24 in a direction opposing the pilot pressures of the inner pilot chambers 12e to 24e. Note that "axially inward" refers to the direction in which each spool 12 to 27 moves away from the openings of the spool holes 11b, 11c.

[0053] The spring mechanisms 12d to 27d are housed in the spool covers 61 to 68, 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.

[0054] The first solenoid valves 12a to 24a and the second solenoid valves 12b to 27c are respectively provided on corresponding spool covers 61 to 68. The corresponding spool covers 68 are as follows: That is, as described above, each of the solenoid valves 12a to 24a and 12b to 27c corresponds to a corresponding spool 12 to 27. Each of the solenoid valves 12a to 24a and 12b to 27c outputs pilot pressure to the corresponding spool 12 to 27. For each of the solenoid valves 12a to 24a and 12b to 27c, the corresponding spool cover 61 to 68 covers the spool hole 11b, 11c into which the corresponding spool 12 to 27 is inserted. The first solenoid valves 12a to 24a and the second solenoid valves 12b to 27b output pilot pressures that act in directions opposing each other to the corresponding spool 12 to 27. More specifically, the first solenoid valves 12a to 24a are connected to the inner pilot chambers 12e to 24e, respectively. Each of the first solenoid valves 12a to 24a outputs a pilot pressure to the corresponding inner pilot chamber 12e to 24e. On the other hand, the second solenoid valves 12b to 27b are connected to the outer pilot chambers 12f to 27f, respectively. Each of the second solenoid valves 12b to 27b outputs a pilot pressure to the corresponding outer pilot chamber 12f to 27f. Each of the solenoid valves 12a to 24a and 12b to 27b outputs a pilot pressure to the corresponding spool 12 to 24 in accordance with an input signal.

[0055] In this way, the first solenoid valves 12a to 24a and the second solenoid valves 12b to 27b output pilot pressures to the pilot chambers 12e to 24e and 12f to 27f, respectively. Therefore, the pilot pressures of the solenoid valves 12a to 24a and 12b to 24b act in opposing directions on the corresponding spools 12 to 24. Furthermore, the pilot pressures of the second solenoid valves 25b to 27b act axially inward on the corresponding spools 25 to 26. The biasing forces of the spring mechanisms 12d to 27d also act on the corresponding spools 12 to 27 in opposing directions to the pilot pressures from the first solenoid valves 12a to 24a and the 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 forces of the spring mechanisms 12d to 27d are balanced. As a result, each of the spools 12 to 27 controls the flow of hydraulic fluid in response to a signal input to each of the solenoid valves 12a to 24a and 12b to 27b.

[0056] As described above, each of the solenoid valves 12a to 24a and 12b to 27b configured in this manner is provided on a corresponding spool cover 61 to 68. The spool covers 61 to 68 are basically configured in the same manner. However, the first spool covers 61 and 62 that cover the spools 20 and 26 and the spools 25 and 27, respectively, differ from the other spool covers 63 to 68 in that they each have a single first pilot passage 60f, which will be described in detail later. Therefore, the following description will focus on the configuration of the spool cover 63 that covers the spools 17 and 24, as shown in FIG. 5, and will omit a description of the configurations of the other spool covers 61, 62, 64 to 68.

[0057] In addition to the outer pilot chambers 17f and 24f, the spool cover 63 includes a primary pressure chamber 60b, a drain chamber 60c, a primary pressure supply passage 60d, a drain passage 60e, a first pilot passage 60f, and a second pilot passage 60g. The spool cover 63 also includes a pair of solenoid valves 17a and 17b corresponding to the spool 17 and a pair of solenoid valves 24a and 24b corresponding to the spool 24. That is, the spool cover 63 is provided with four solenoid valves 17a, 24a, 17b, and 24b.

[0058] The four solenoid valves 17a, 24a, 17b, and 24b extend in the height direction. The four solenoid valves 17a, 24a, 17b, and 24b are arranged side by side in the depth direction, as shown in FIG. 1 . More specifically, the four solenoid valves 17a, 24a, 17b, and 24b are arranged on the spool cover 63 in a V-shape, pointed outward in the width direction. Note that the "outward in the width direction" refers to the side opposite the adjacent sides of two adjacent spool covers 63. In this embodiment, the four solenoid valves 17a, 24a, 17b, and 24b are arranged as follows in a plan view: The second solenoid valves 17b and 24b are arranged, for example, at intervals in the depth direction of the spool cover 63, and the first solenoid valves 17a and 24a are arranged between the second solenoid valves 17b and 24b. In addition, the solenoid valves 17a, 17b are arranged so that at least a portion thereof overlaps the corresponding arm rod side spool 17 in a planar view, and the solenoid valves 24a, 24b are arranged so that at least a portion thereof overlaps the corresponding bucket rod side spool 24 in a planar view.

[0059] The solenoid valves 17a, 24a, 17b, and 24b are configured, for example, as follows. That is, the solenoid valves 17a, 24a, 17b, and 24b include a valve portion 71 and a solenoid 72. The valve portion 71 has a primary port 71a, a secondary port 71b, and a drain port 71c. More specifically, the valve portion 71 extends in its axial direction, which in this embodiment is also the height direction, and is fitted into the spool cover 63. The primary port 71a, the secondary port 71b, and the drain port 71c are formed in the valve portion 71 in this order from the tip end.

[0060] In addition, in the solenoid valves 17a, 24a, 17b, and 24b, the primary port 71a is connected to the primary pressure chamber 60b, and the drain port 71c is connected to the drain chamber 60c. The secondary port 71b of the first solenoid valves 17a and 24a is connected to the first pilot passage 60f, and the secondary port 71b of the second solenoid valves 17b and 24b is connected to the second pilot passage 60g. That is, the valve portion 71 of the first solenoid valves 17a and 24a is connected to the primary pressure chamber 60b at a middle portion in the height direction, the first pilot passage 60f at a tip portion, and the drain chamber 60c at a base end portion. In addition, the valve portion 71 of the second solenoid valves 17b and 24b is connected to the primary pressure chamber 60b at a middle portion in the height direction, the second pilot passage 60g at a tip portion, and the drain chamber 60c at a base end portion. A primary pressure supply passage 60d is connected to the primary pressure chamber 60b, and a drain passage 60e is connected to the drain chamber 60c (see also FIG. 6).

[0061] The primary pressure supply passage 60d supplies primary pressure to the primary pressure chamber 60b. More specifically, the primary pressure supply passage 60d is connected to the pressure source passage 11g, as described later in detail (see FIG. 5). Primary pressure is supplied to the primary pressure supply passage 60d from the pressure source passage 11g, and primary pressure is supplied to the primary pressure chamber 60b from the pressure source passage 11g via the primary pressure supply passage 60d. The drain passage 60e drains hydraulic fluid from the drain chamber 60c. The drain passage 60e is connected to the tank passage 33, as described later in detail, and allows the primary pressure to be drained to the tank 30 via the tank passage 33 (see FIG. 4). Furthermore, the first pilot passage 60f is connected to the inner pilot chambers 17e and 24e, and the second pilot passage 60g is connected to the outer pilot chambers 17f and 24f.

[0062] The solenoid 72 strokes the valve element (not shown) of the valve unit 71 in response to an input signal. The valve element 71 adjusts the opening of each of the solenoid valves 17a, 24b, 17b, and 24b by stroking. More specifically, in each of the solenoid valves 17a, 24b, 17b, and 24b, the primary port 71a is connected to the drain port 71c in the normal state, and the opening between the drain port 71c and the secondary port 71b is adjusted by stroking the valve element. Therefore, the solenoid valves 17a, 24b, 17b, and 24b can adjust the pilot pressures output to the pilot chambers 17e, 24e, 17f, and 24f to pressures corresponding to the signal by stroking the valve element.

[0063] The chambers 17f, 24f, 60b, and 60c and the passages 60d to 60g are formed in the spool cover 63 as follows. That is, as shown in FIG. 5 , the outer pilot chambers 17f and 24f, the primary pressure chamber 60b, and the drain chamber 60c are arranged in the height direction of the spool cover 63, in this order from the valve block 11 side (one heightwise end of the spool cover 63 in this embodiment) (see also FIG. 6 ). The outer pilot chambers 17f and 24f extend in the height direction and are formed on one heightwise end side of the spool cover 63. As shown in FIG. 5 , the outer pilot chambers 17f and 24f are arranged apart in the depth direction of the spool cover 63. That is, the outer pilot chambers 17f and 24f are located on one and the other depthwise sides of the spool cover 63. As described above, the outer pilot chambers 17f and 24f house the spring mechanisms 17d and 24d. In this embodiment, the outer pilot chambers 17f, 24f are formed in the spool cover 63 so that their axes coincide with the axes of the spool holes 11b into which the spools 17, 24 are inserted.

[0064] The primary pressure chamber 60b is, for example, a flat space and extends in the depth direction (see FIGS. 6 and 5). The primary pressure chamber 60b is formed to connect the primary ports 71a of the valve portions 71 of the four solenoid valves 17a, 24a, 17b, and 24b in a plan view. In this embodiment, the primary pressure chamber 60b is, for example, a V-shaped flat space in a plan view. The primary pressure chamber 60b is connected to the middle portions of the valve portions 71 of the four solenoid valves 17a, 24a, 17b, and 24b.

[0065] The drain chamber 60c is also, for example, a flat space and extends in the depth direction (see FIGS. 5 and 6 ). The drain chamber 60c is formed to be connected to each of the drain ports 71c of the valve portions 71 of the four solenoid valves 17a, 24a, 17b, and 24b. In this embodiment, the drain chamber 60c is, for example, a flat space having a trapezoidal shape in a plan view and is connected to each of the drain ports 71c of the solenoid valves 17a, 24a, 17b, and 24b. The drain chamber 60c is connected to the proximal end of the valve portions 71 of the four solenoid valves 17a, 24a, 17b, and 24b relative to the primary pressure chamber 60b. In this embodiment, the drain chamber 60c is connected to the proximal end of the valve portions 71 of the four solenoid valves 17a, 24a, 17b, and 24b.

[0066] As shown in FIG. 6 , the primary pressure supply passage 60d is connected to the primary pressure chamber 60b as described above. The primary pressure supply passage 60d extends vertically in the spool cover 63. The primary pressure supply passage 60d is connected to the pressure source passage 11g. The pressure source passage 11g is formed in the valve block 11. The pressure source passage 11g is connected to a pilot pump (not shown), which serves as a pressure source, and primary pressure is supplied from the pilot pump. More specifically, the pressure source passage 11g is connected to the primary pressure supply passages 60d of each spool cover 63. In this embodiment, the pressure source passage 11g is formed near both vertical side surfaces of the valve block 11 and branches to connect to the primary pressure supply passages 60d of each spool cover 63. The primary pressure supply passage 60d thus formed is positioned in the spool cover 63, separated in the width direction from the drain passage 60e, which will be described in detail later. More specifically, the primary pressure supply passage 60d is disposed between the two outer pilot chambers 17f, 24f in a side view in the width direction (see FIG. 5). In this embodiment, the primary pressure supply passage 60d is disposed between the two first solenoid valves 17a, 24a in a side view, and is connected to the tip end of the V-shaped primary pressure chamber 60b. In other words, the primary pressure supply passage 60d is disposed on the outer side in the width direction of the spool cover 63.

[0067] As described above, the drain passage 60e is connected to the drain chamber 60c. The drain passage 60e extends in the height direction in the spool cover 63. The drain passage 60e is connected to the tank passage 33 in the valve block 11. The tank passage 33 is formed in the valve block 11 to connect each of the spools 12 to 27 and is connected to the drain passages 60e in each spool cover 63 via passages branching from the tank passage 33. As described above, the drain passage 60e formed in this manner is disposed in the spool cover 63, separated from the primary pressure supply passage 60d in the width direction. More specifically, as shown in FIG. 5, the drain passage 60e is disposed between the two outer pilot chambers 17f, 24f in a side view. In this embodiment, the drain passage 60e is disposed so as to overlap with the primary pressure supply passage 60d in a side view and is connected to the inner portion of the drain chamber 60c in the width direction (see also FIG. 4). That is, the drain passage 60e is disposed on the other widthwise inner side of the spool cover 63. The widthwise inner side refers to the side where two spool covers 63 that are adjacent to each other in the width direction are adjacent to each other.

[0068] As described above, the first pilot passage 60f is connected to the tip side of the valve portion 71 of the first solenoid valve 17a, 24a (in this embodiment, the secondary port 71b). The first pilot passage 60f extends in the height direction of the spool cover 63. In this embodiment, the first pilot passage 60f is bent in a crank shape so as to avoid the outer pilot chambers 17f, 24f. More specifically, the first solenoid valves 17a, 24a are disposed so as to overlap the outer pilot chambers 17f, 24f in a plan view, and the secondary port 71b is formed at the tip of the first solenoid valve 17a, 24a (i.e., the tip of the valve portion 71). Therefore, the first pilot passage 60f is bent in a crank shape so as to avoid the outer pilot chambers 17f, 24f. In this embodiment, the first pilot passage 60f extends in the height direction from the secondary port 71b toward the outer pilot chambers 17f, 24f, then bends and extends inward in the width direction toward the drain passage 60e. The first pilot passage 60f then bends again near the drain passage 60e and extends in the height direction toward the valve block 11. The first pilot passage 60f is connected to the inner pilot chambers 17e, 24e via block-side pilot passages 11h formed in the valve block 11. The first solenoid valves 17a, 24a are arranged to sandwich the drain passage 60e therebetween in a side view as shown in FIG. 7 , and the first pilot passages 60f are arranged on both sides of the drain passage 60e in the depth direction so as to be aligned with the drain passage 60e.

[0069] As shown in FIG. 5 , as described above, the second pilot passage 60g is connected to the tip side of the valve portion 71 of the second solenoid valve 17b, 24b (in this embodiment, the secondary port 71b). The second pilot passage 60g extends in the height direction of the spool cover 63. The second pilot passage 60g is connected to each of the outer pilot chambers 17f, 24f. More specifically, the primary port 71a is formed at the tip of each of the second solenoid valves 17b, 24b (i.e., the tip of the valve portion 71). The second solenoid valves 17b, 24b are arranged to overlap the outer pilot chambers 17f, 24f in a plan view and are eccentrically positioned outward in the depth direction relative to the outer pilot chambers 17f, 24f. More specifically, the second solenoid valves 17b, 24b are arranged such that their axes are positioned outward in the depth direction relative to the axes of the outer pilot chambers 17f, 24f. As a result, each of the second pilot passages 60g is also disposed eccentrically outward in the depth direction relative to the outer pilot chambers 17f, 24f. The second pilot passages 60g extend straight in the height direction from the tips of the second solenoid valves 17b, 24b and are connected to the outer pilot chambers 17f, 24f, respectively.

[0070] In the multi-control valve 1 configured as described above, pilot pressure is output from the solenoid valves 12a to 24a and 12b to 27b as follows. That is, in the spool covers 61 to 68, primary pressure is introduced to the primary pressure chamber 60b from the pressure source passage 11g via the primary pressure supply passage 60d. The solenoid valves 12a to 24a and 12b to 27b adjust the opening of the drain port 71c and the secondary port 71b relative to the primary port 71a in response to an input signal. As a result, the solenoid valves 12a to 24a and 12b to 27b adjust the primary pressure introduced from the primary pressure chamber 60b to the primary port 71a and output pilot pressures of pressures corresponding to the signals to the respective pilot passages 60f and 60g via the secondary port 71b. As a result, pilot pressures corresponding to the signals are output from the solenoid valves 12a to 24a and 12b to 27b to the pilot chambers 12e to 24e and 12f to 27f, respectively, and the spools 12 to 27 stroke.

[0071] <Flow of hydraulic fluid in the multi-control valve> In the multi-control valve 1, the breaker spools 25, 26 have an unloading function, and in the normal state, they discharge (i.e., bleed off) hydraulic fluid from the hydraulic pumps 9, 10 to the tank 30. This places the hydraulic pumps 9, 10 in an unloaded state. On the other hand, when driving each of the actuators 2 to 7, the breaker spools 25, 26 limit the flow rate of hydraulic fluid bled off from the hydraulic pumps 9, 10 to the tank 30 in accordance with the pilot pressure output from the solenoid valves 25b, 26b. This allows hydraulic fluid to be supplied to each of the actuators 2 to 7. Furthermore, the multi-control valve 1 operates as follows to drive each of the actuators 2 to 8.

[0072] 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.

[0073] 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.

[0074] 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 in the head-side port 6a. On the other hand, when the arm cylinder 6 is to be retracted, the multi-control valve 1 outputs pilot pressure from the solenoid valves 14a and 16b. This 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.

[0075] 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.

[0076] 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.

[0077] Furthermore, when the multi-control valve 1 operates the hydraulic breaker 8, the following occurs: pilot pressure is output from the solenoid valves 25b and 26b and directed to the outer pilot chambers 25f and 26f. Then, hydraulic fluid is supplied to the hydraulic breaker 8 from the hydraulic pumps 9 and 10 via the breaker spools 25 and 26. This drives the hydraulic breaker 8.

[0078] 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.

[0079] 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 reduces the difference in hydraulic pressure between the hydraulic fluid guided to the first traveling spool 12 and the second traveling spool 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.

[0080] In the multi-control valve 1 of this embodiment, the spool cover 63 covers two spool holes 11b. This reduces the number of covers that cover the spools 17 and 24, thereby reducing the number of parts in the multi-control valve 1. In addition, two pairs of solenoid valves 17a, 17b, 24a, 24b are provided on the spool cover 63. This allows the solenoid valves 17a, 24a, 17b, and 24b to be laid out compactly.

[0081] Furthermore, in the multi-control valve 1 of this embodiment, the first pilot passage 60f extends in the height direction of the spool cover 63. Also, the second pilot passage 60g extends in the height direction of the spool cover 63. Therefore, the shapes of the first pilot passage 60f and the second pilot passage 60g are simple, and the spool cover 63 is easy to manufacture.

[0082] Furthermore, in the multi-control valve 1 of this embodiment, each of the second solenoid valves 17b, 24b is provided on the spool cover 63 eccentrically outward in the depth direction relative to the outer pilot chambers 17f, 24f to which it is connected. This allows each of the second solenoid valves 17b, 24b to be disposed closer to the outside in the depth direction on the spool cover 63. This ensures space for disposing the first solenoid valves 17a, 24a between the second solenoid valves 17b, 24b, allowing the spool cover 63 to be designed compactly.

[0083] Furthermore, in the multi-control valve 1 of this embodiment, the primary pressure supply passage 60d extends in the first direction in the spool cover 63 and is connected to the pressure source passage 11g of the valve block 11, and the drain passage 60e extends in the height direction in the spool cover 63 and is connected to the tank passage 33 of the valve block 11. Therefore, the structure for supplying primary pressure and draining to each of the solenoid valves 17a, 24a, 17b, and 24b can be simplified.

[0084] Furthermore, in the multi-control valve 1 of this embodiment, the primary pressure supply passage 60d and the drain passage 60e are arranged at a distance in the width direction on the spool cover 63. Therefore, they can be arranged on one side and the other side in the width direction on the spool cover, respectively, so that the two passages 60d, 60e can be formed compactly while ensuring the strength of the spool cover 63.

[0085] Furthermore, in the multi-control valve 1 of this embodiment, the outer pilot chambers 17f, 24f, the primary pressure chamber 60b, and the drain chamber 60c are arranged in the vertical direction in the spool cover 63, in this order from the valve block 11 side, and the second pilot passage 60g is connected to the vertical tip ends of the second solenoid valves 17b, 24b. Therefore, the second pilot passage 60g can be arranged near the outer pilot chambers 17f, 24f. This allows the shape of the second pilot passage 60g to be simplified. This makes it easier to form the spool cover 63.

[0086] Furthermore, in the multi-control valve 1 of this embodiment, the first solenoid valves 17a, 24a are arranged so as to overlap the outer pilot chambers 17f, 24f in a plan view. This allows the solenoid valves 17a, 24a, 17b, and 24b to be laid out compactly in the spool cover 63. In addition, the first pilot passage 60f is bent in a crank shape so as to avoid the outer pilot chambers 17f, 24f. This allows the solenoid valves 17a, 24a, 17b, and 24b to be arranged so as to overlap the outer pilot chambers 17f, 24f in a plan view in the spool cover 63, allowing the solenoid valves 17a, 24a, 17b, and 24b to be laid out compactly.

[0087] Furthermore, in the multi-control valve 1 of this embodiment, the first pilot passages 60f are disposed on both sides of the drain passage 60e in the depth direction in the spool cover 63. Therefore, the first pilot passages 60f, through which a pressure fluid lower than that flowing through the primary pressure supply passage 60d flows, can be disposed around the drain passage 60e. This allows the passages 60e, 60f to be disposed compactly while ensuring the strength of the spool cover 63.

[0088] Furthermore, in the multi-control valve 1 of this embodiment, the valve block 11 is arranged in a row in the vertical direction so that the bottom sides of the first spool holes 11b butt up against the corresponding second spool holes 11c, and spool covers 63 are provided on one and the other end faces in the vertical direction of the valve block 11. This allows the construction of a compact multi-control valve 1.

[0089] The above description has mainly focused on the effects of the spool cover 63. However, the effects described above are not limited to the spool cover 63, and the other spool covers 61, 62, 64 to 68 also provide similar effects.

[0090] [Other Embodiments] In the multi-control valve 1 of this embodiment, the spool covers 61-64 and 65-68 each block two adjacent spool holes 11b and 11c, but they may also be configured to block three or more adjacent spool holes 11b and 11c. Furthermore, the shapes and arrangements of the chambers 12f-27f, 60b, and 60c and the passages 60d-60g in the spool covers 61-68 are all examples, and any configuration is acceptable as long as pilot pressure can be supplied to the solenoid valves 12a-24a and 12b-27b. The arrangements of the solenoid valves 12a-24a and 12b-27b in the spool covers 61-68 are also all examples, and the solenoid valves 12a-24a and 12b-27b may be arranged in a diamond shape in a plan view. Furthermore, the second solenoid valves 12b-27b do not necessarily have to be arranged eccentrically with respect to the outer pilot chambers 12f-27f.

[0091] Furthermore, 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 of this embodiment are all examples, and it is sufficient that the multi-control valve 1 is configured so that the hydraulic circuit 1a functions.

[0092] <Exemplary Embodiment> A multi-control valve in a first aspect includes a valve block including a plurality of spool holes, a plurality of spools that are stroably inserted into the plurality of spool holes and control the flow of hydraulic fluid by stroking, a spool cover group including a plurality of spool covers that close the plurality of spool holes, and a solenoid valve group including a plurality of pairs of solenoid valves corresponding to each of the plurality of spools, the solenoid valve group including a plurality of pairs of solenoid valves that output pilot pressures that act in directions opposing each other to the corresponding spools, and the pair of solenoid valves are provided on the corresponding spool covers.

[0093] According to the above aspect, the spool cover covers multiple spool holes. This reduces the number of covers that are placed over the spool, thereby reducing the number of parts in the multi-control valve. Furthermore, multiple pairs of solenoid valves are provided on the spool cover. This allows for a compact layout of the solenoid valves.

[0094] In a second aspect, in the multi-control valve of the first aspect, the spool hole includes an inner pilot chamber defined by the spool, the spool cover includes an outer pilot chamber, a first solenoid valve of the pair of solenoid valves is connected to the inner pilot chamber via a first pilot passage, a second solenoid valve of the pair of solenoid valves is connected to the outer pilot chamber via a second pilot passage, the first pilot passage extends in a first direction in the spool cover, and the second pilot passage extends in the first direction in the spool cover.

[0095] According to the above aspect, the first pilot passage extends in the first direction in the spool cover. Also, the second pilot passage extends in the first direction in the spool cover. Therefore, since the shapes of the first and second pilot passages are simple, the spool cover can be easily manufactured.

[0096] In a multi-control valve of a third aspect, in the multi-control valve of the second aspect, the first and second solenoid valves are arranged side by side in a second direction intersecting the first direction on the spool cover, the outer pilot chambers are arranged in the spool cover to extend in the first direction and spaced apart from each other in the second direction, and each of the second solenoid valves is provided on the spool cover eccentrically outward in the second direction relative to the outer pilot chamber to which it is connected.

[0097] According to the above aspect, each of the second solenoid valves is provided on the spool cover eccentrically outward in the second direction relative to the outer pilot chamber to which it is connected. This allows each of the second solenoid valves to be disposed closer to the outside in the second direction on the spool cover. This ensures space for disposing the first solenoid valve between the second solenoid valves, allowing the spool cover to be designed compactly.

[0098] In a multi-control valve of a fourth aspect, in the multi-control valve of the second or third aspect, the spool cover includes a primary pressure chamber that supplies primary pressure to each of the first and second solenoid valves, a primary pressure supply passage that supplies primary pressure to the primary pressure chamber, a drain chamber connected to each of the first and second solenoid valves, and a drain passage that discharges working fluid from the drain chamber, and the primary pressure supply passage extends in a first direction in the spool cover and is connected to a pressure source passage of the valve block, and the drain passage extends in the first direction in the spool cover and is connected to a tank passage of the valve block.

[0099] According to the above aspect, the primary pressure supply passage extends in the first direction in the spool cover and connects to the pressure source passage in the valve block, and the drain passage extends in the first direction in the spool cover and connects to the tank passage in the valve block, thereby simplifying the structure for supplying primary pressure to and draining from each solenoid valve.

[0100] In a multi-control valve in a fifth aspect, in the multi-control valve of the fourth aspect, the primary pressure supply passage and the drain passage are arranged in the spool cover and spaced apart in a third direction that intersects with the first and second directions.

[0101] In accordance with the above aspect, the primary pressure supply passage and the drain passage are arranged in the spool cover so as to be spaced apart in the third direction intersecting the first and second directions, and therefore can be arranged on one side and the other side of the spool cover 63 in the third direction, respectively, making it possible to compact the two passages while ensuring the strength of the spool cover.

[0102] In a multi-control valve of a sixth aspect, in the multi-control valve of any one of the second to fifth aspects, the spool cover includes a primary pressure chamber that supplies primary pressure to each of the first and second solenoid valves, and a drain chamber that is connected to each of the first and second solenoid valves, and the spool cover has the outer pilot chamber, the primary pressure chamber, and the drain chamber arranged in a first direction from the valve block side, and the second pilot passage is connected to the first direction tip side of the second solenoid valve.

[0103] According to the above aspect, the outer pilot chamber, the primary pressure chamber, and the drain chamber are arranged in the spool cover in the first direction, in that order from the valve block side, and the second pilot passage is connected to the tip side of the second solenoid valve in the first direction. This allows the second pilot passage to be arranged near the outer pilot chamber. This simplifies the shape of the second pilot passage, which makes it easier to form the spool cover.

[0104] In a multi-control valve of a seventh aspect, in the multi-control valve of any one of the second to sixth aspects, the first solenoid valve is arranged so as to overlap the outer pilot chamber when viewed in a first direction, and the first pilot passage is bent in a crank shape so as to avoid the outer pilot chamber.

[0105] According to the above aspect, the first solenoid valve is disposed so as to overlap the outer pilot chamber when viewed in the first direction. This allows the solenoid valve to be laid out compactly in the spool cover. Furthermore, the first pilot passage is bent in a crank shape in the third direction so as to avoid the outer pilot chamber. This allows the solenoid valve to be disposed so as to overlap the outer pilot chamber in a plan view in the spool cover, allowing the solenoid valve to be laid out compactly.

[0106] In an eighth aspect of the present invention, in the multi-control valve of the fourth or fifth aspect, the first pilot passages are arranged on both sides of the drain passage in the second direction in the spool cover.

[0107] According to the above aspect, the first pilot passage is disposed on each side of the drain passage in the second direction in the spool cover. Therefore, the first pilot passage, through which a pressure fluid lower than that flowing through the primary pressure supply passage flows, can be disposed around the drain passage. This allows the passages to be disposed compactly while ensuring the strength of the spool cover.

[0108] In a ninth aspect of the multi-control valve, in the multi-control valve of any one of the second to eighth aspects, the plurality of spool holes include a plurality of first spool holes and a plurality of second spool holes formed in one end face and the other end face in a first direction of the valve block, each of the first spool holes is arranged corresponding to the second spool hole and is arranged in a row in the first direction so that the bottom sides of the first spool holes butt against the corresponding second spool holes, and the spool covers are provided on the one end face and the other end face in the first direction of the valve block.

[0109] According to the above aspect, in a valve block in which the first spool holes are aligned in a row in the first direction so that the bottom sides of the first spool holes abut against the corresponding second spool holes, spool covers are provided on one end surface and the other end surface in the first direction of the valve block, thereby enabling the construction of a compact multi-control valve.

[0110] 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 comprising: a valve block including a plurality of spool holes; a plurality of spools that are swivelably inserted into the plurality of spool holes and control the flow of hydraulic fluid by stroking; a spool cover group including a plurality of spool covers that close the plurality of spool holes; and a solenoid valve group including a plurality of pairs of solenoid valves corresponding to each of the plurality of spools, the solenoid valve group including a plurality of pairs of solenoid valves that respectively output pilot pressures that act in directions opposing each other to the corresponding spools, wherein the pair of solenoid valves are provided on the corresponding spool covers.

2. A multi-control valve as set forth in claim 1, wherein the spool hole includes an inner pilot chamber defined by the spool, the spool cover includes an outer pilot chamber, a first solenoid valve of the pair of solenoid valves is connected to the inner pilot chamber via a first pilot passage, and a second solenoid valve of the pair of solenoid valves is connected to the outer pilot chamber via a second pilot passage, the first pilot passage extends in a first direction in the spool cover, and the second pilot passage extends in the first direction in the spool cover.

3. A multi-control valve as described in claim 2, wherein the first and second solenoid valves are arranged side by side in a second direction intersecting the first direction on the spool cover, the outer pilot chambers are arranged in the spool cover extending in the first direction and spaced apart from each other in the second direction, and each of the second solenoid valves is provided on the spool cover eccentrically outward in the second direction relative to the outer pilot chamber to which it is connected.

4. A multi-control valve as described in claim 2, wherein the spool cover includes a primary pressure chamber that supplies primary pressure to each of the first and second solenoid valves, a primary pressure supply passage that supplies primary pressure to the primary pressure chamber, a drain chamber connected to each of the first and second solenoid valves, and a drain passage that discharges working fluid from the drain chamber, wherein the primary pressure supply passage extends in a first direction in the spool cover and is connected to a pressure source passage in the valve block, and wherein the drain passage extends in the first direction in the spool cover and is connected to a tank passage in the valve block.

5. A multi-control valve according to claim 4, wherein the primary pressure supply passage and the drain passage are arranged in the spool cover so as to be spaced apart in a third direction intersecting the first and second directions.

6. A multi-control valve as described in claim 2, wherein the spool cover includes a primary pressure chamber that supplies primary pressure to each of the first and second solenoid valves, and a drain chamber that is connected to each of the first and second solenoid valves, and the spool cover has the outer pilot chamber, the primary pressure chamber, and the drain chamber arranged in a first direction in that order from the valve block side, and the second pilot passage is connected to the tip side of the second solenoid valve in the first direction.

7. A multi-control valve as described in claim 2, wherein the first solenoid valve is arranged to overlap the outer pilot chamber when viewed in the first direction, and the first pilot passage is bent in a crank shape to avoid the outer pilot chamber.

8. A multi-control valve as set forth in claim 44, wherein the first pilot passages are disposed on both sides of the drain passage in the second direction in the spool cover.

9. A multi-control valve as described in claim 2, wherein the plurality of spool holes include a plurality of first spool holes and a plurality of second spool holes formed on one end face and the other end face in the first direction of the valve block, each of the first spool holes is arranged corresponding to one of the second spool holes and is arranged in a row in the first direction so that the bottom sides of the first spool holes butt up against the corresponding second spool holes, and the spool covers are provided on the one end face and the other end face in the first direction of the valve block.

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