Fluid system, construction machine, and control method

Abstract

To provide a fluid valve, a fluid system, a construction machine and a control method capable of saving energy.SOLUTION: A fluid valve 14 comprises: a valve body having a spool hole 20 and a discharge port D2 connected to the spool hole 20; and a spool 15 movably provided in the spool hole 20. When the spool 15 is moved in one direction, the discharge port D2 is connected to at least one of a regeneration flow path 37 and a tank flow path 136.SELECTED DRAWING: Figure 5

Description

[Technical field]

[0001] The present invention relates to a fluid valve, a fluid system, a construction machine, and a control method. [Background technology]

[0002] For example, a construction machine such as a hydraulic excavator is driven by a hydraulic system having a hydraulic actuator. For example, the hydraulic actuator is driven by hydraulic oil discharged from a pump (hydraulic pump). For example, the hydraulic system includes a fluid valve (hydraulic valve) that controls the flow rate of the hydraulic oil discharged from the pump. For example, the hydraulic valve includes a valve body and a spool. The valve body has a spool hole and a flow path connected to the spool hole. The spool is movably provided in the spool hole. For example, in Patent Document 1, the movement of the spool causes hydraulic oil from one pump to flow from the hydraulic valve. The hydraulic oil from one pump flows from the hydraulic valve through the flow path to the hydraulic actuator. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2004-360751 A Summary of the Invention [Problem to be solved by the invention]

[0004] When an actuator is driven by a fluid, it is desirable to save energy.

[0005] The present invention has been made to solve the above-mentioned problems, and has an object to provide a fluid valve, a fluid system, a construction machine, and a control method that can save energy. [Means for solving the problem]

[0010] (1) A fluid system according to an aspect of the present invention is a fluid system comprising: a pump that discharges a fluid; and a fluid control device having a fluid valve that controls the flow rate of the fluid discharged from the pump and flows it to an actuator, wherein the fluid valve comprises a valve body having a first spool hole, a second spool hole, and a discharge port connected to the second spool hole, a meter-in spool movably provided in the first spool hole, and a meter-out spool movably provided in the second spool hole, and the fluid control device further comprises a first solenoid valve and a second solenoid valve that move the meter-in spool and the meter-out spool, respectively, and a control unit that controls the first solenoid valve and the second solenoid valve, and wherein when the meter-out spool is moved in one direction, the discharge port is connected to at least one of a regeneration flow path and a tank flow path. The discharge port is a port that communicates with a head port or a rod port of a cylinder that constitutes the actuator and discharges fluid from the head port or the rod port to a tank, and the regeneration flow path is a flow path for utilizing the fluid from the head port or the rod port to drive the pump or the actuator. .

[0011] According to this configuration, when the discharge port is connected to the regeneration flow path by the movement of the spool in one direction, the fluid from the discharge port can be used to regenerate the actuator, thereby saving energy.

[0014] (2) A construction machine according to an aspect of the present invention is a construction machine comprising: a boom; a pump that discharges a fluid; a fluid control device having a fluid valve that controls the flow rate of the fluid discharged from the pump; and an actuator for driving the boom by flowing the fluid whose flow rate is controlled by the fluid valve, wherein the fluid valve comprises a valve body having a first spool hole, a second spool hole, and a discharge port connected to the second spool hole; a meter-in spool that is movably provided in the first spool hole and controls the amount of fluid supplied to the actuator; and a meter-out spool that is movably provided in the second spool hole and controls the amount of fluid discharged from the actuator, and the fluid control device further comprises a solenoid valve that moves the meter-out spool, and a control unit that controls the solenoid valve, and when the meter-out spool is moved in one direction, the discharge port is connected to the regeneration flow path. The discharge port is a port that communicates with a head port or a rod port of a cylinder that constitutes the actuator and discharges fluid from the head port or the rod port to a tank, and the regeneration flow path is a flow path for utilizing the fluid from the head port or the rod port to drive the pump or the actuator. .

[0015] According to this configuration, the unidirectional movement of the meter-out spool connects the discharge port to the regeneration flow path, allowing the fluid from the discharge port to be used (regenerated) to drive the actuator, thereby achieving energy savings with a simple configuration. In addition, by including a meter-in spool that controls the amount of fluid supplied to the actuator, the fluid valve can easily adjust the amount of fluid supplied to the actuator in response to fluctuations in the load on the actuator. In addition, by including a meter-out spool that controls the amount of fluid discharged from the actuator, the fluid valve can easily adjust the amount of fluid discharged from the actuator in response to fluctuations in the load on the actuator. In addition, by including a solenoid valve that moves the meter-out spool and a control unit that controls the solenoid valve, the fluid control device can electrically adjust the drive control of the meter-out spool, thereby simplifying the circuit configuration.

[0016] (3) A construction machine according to an aspect of the present invention is a construction machine comprising: a boom; a pump that discharges a fluid; a fluid control device having a fluid valve that controls the flow rate of the fluid discharged from the pump; and an actuator for driving the boom by flowing the fluid whose flow rate is controlled by the fluid valve, wherein the fluid valve comprises a valve body having a first spool hole, a second spool hole, and a discharge port connected to the second spool hole; a meter-in spool that is movably provided in the first spool hole and controls the amount of fluid supplied to the actuator; and a meter-out spool that is movably provided in the second spool hole and controls the amount of fluid discharged from the actuator, and the fluid control device further comprises a solenoid valve that moves the meter-out spool, and a control unit that controls the solenoid valve, and when the meter-out spool is moved in one direction, the discharge port is connected to the first spool hole. The discharge port is a port that communicates with a head port or a rod port of a cylinder that constitutes the actuator and discharges fluid from the head port or the rod port to a tank. .

[0017] According to this configuration, the unidirectional movement of the meter-out spool connects the discharge port to the first spool hole, allowing the fluid from the discharge port to be used (regenerated) to drive the fluid valve, thereby achieving energy savings with a simple configuration. In addition, by including a meter-in spool that controls the amount of fluid supplied to the actuator, the fluid valve can easily adjust the amount of fluid supplied to the actuator in response to fluctuations in the load on the actuator. In addition, by including a meter-out spool that controls the amount of fluid discharged from the actuator, the fluid valve can easily adjust the amount of fluid discharged from the actuator in response to fluctuations in the load on the actuator. In addition, by including a solenoid valve that moves the meter-out spool and a control unit that controls the solenoid valve, the fluid control device can electrically adjust the drive control of the meter-out spool, thereby simplifying the circuit configuration.

[0018] (4) A construction machine according to an aspect of the present invention is a construction machine comprising: a boom; a pump that discharges a fluid; a fluid control device having a fluid valve that controls the flow rate of the fluid discharged from the pump; and an actuator for driving the boom by flowing the fluid whose flow rate is controlled by the fluid valve, wherein the fluid valve comprises a valve body having a first spool hole, a second spool hole, and a discharge port connected to the second spool hole; a meter-in spool that is movably provided in the first spool hole and controls the amount of fluid supplied to the actuator; and a meter-out spool that is movably provided in the second spool hole and controls the amount of fluid discharged from the actuator, and the fluid control device further comprises a solenoid valve that moves the meter-out spool, and a control unit that controls the solenoid valve, and when the meter-out spool is moved in one direction, the discharge port is connected to another actuator different from the actuator. The discharge port is a port that communicates with a head port or a rod port of a cylinder that constitutes the actuator and discharges fluid from the head port or the rod port to a tank. .

[0019] According to this configuration, the unidirectional movement of the meter-out spool connects the discharge port to another actuator, allowing the fluid from the discharge port to be used (regenerated) to drive the other actuator, thereby achieving energy savings with a simple configuration. In addition, by including a meter-in spool that controls the amount of fluid supplied to the actuator, the fluid valve can easily adjust the amount of fluid supplied to the actuator in response to fluctuations in the load on the actuator. In addition, by including a meter-out spool that controls the amount of fluid discharged from the actuator, the fluid valve can easily adjust the amount of fluid discharged from the actuator in response to fluctuations in the load on the actuator. In addition, by including a solenoid valve that moves the meter-out spool and a control unit that controls the solenoid valve, the fluid control device can electrically adjust the drive control of the meter-out spool, thereby simplifying the circuit configuration.

[0020] (5) A control method according to an aspect of the present invention includes: a control method for a construction machine comprising: a boom; a pump that discharges a fluid; a fluid valve that controls the flow rate of the fluid discharged from the pump; and an actuator for driving the boom by flowing the fluid whose flow rate is controlled by the fluid valve, wherein the fluid valve comprises a valve body having a first spool hole, a second spool hole, and a first discharge port and a second discharge port connected to the second spool hole, a meter-in spool movably provided in the first spool hole and controlling the amount of fluid supplied to the actuator, and a meter-out spool movably provided in the second spool hole and controlling the amount of fluid discharged from the actuator, The method includes a raising step of raising a boom and a lowering step of lowering the boom. the first discharge port is a port that communicates with a rod port of a cylinder that constitutes the actuator and that discharges fluid from the rod port to a tank, the second discharge port is a port separate from the first discharge port and that communicates with a head port of the cylinder, In the raising step, Meter-out spool Move in one direction The first exhaust port The fluid from the tank is returned to the tank, and in the descending step, Meter-out spool Move in the other direction The second exhaust port Regenerating said fluid from do .

[0021] According to this method, by regenerating the fluid from the discharge port during the lowering process, the fluid from the discharge port can be used (regenerated) to drive the actuator during the boom lowering operation, thereby saving energy. Effect of the Invention

[0022] According to the present invention, it is possible to provide a fluid valve, a fluid system, a construction machine, and a control method that can save energy. [Brief description of the drawings]

[0023] [Figure 1] FIG. 1 is a schematic diagram of a construction machine according to a first embodiment. [Diagram 2] FIG. 1 is a schematic diagram of a hydraulic system according to a first embodiment. [Diagram 3] FIG. 5 is an explanatory diagram of an example of an operation of the hydraulic system when the meter-in spool in the first embodiment is located in a neutral position. [Figure 4] FIG. 4 is an explanatory diagram of an example of the operation of the hydraulic system when raising a boom in the first embodiment. [Diagram 5] FIG. 4 is an explanatory diagram of an example of the operation of the hydraulic system when lowering a boom in the first embodiment. [Figure 6] FIG. 11 is an explanatory diagram of an example of the operation of the hydraulic system when lowering a boom in the second embodiment. [Figure 7] 13 is an explanatory diagram of an example of the operation of the hydraulic system when driving the actuator of the third embodiment. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0024] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In the following embodiment, a hydraulic excavator equipped with a hydraulic system (fluid system) will be described as an example of a construction machine. Note that in the drawings used in the following description, the scale of each component is appropriately changed so that each component is of a recognizable size.

[0025] First Embodiment <Construction machinery> FIG. 1 is a schematic diagram of a construction machine 100 according to a first embodiment. As shown in Fig. 1, the construction machine 100 is, for example, a hydraulic excavator. The construction machine 100 includes a revolving body 101 and a running body 102. The revolving body 101 is provided on the running body 102 so as to be able to revolve. The revolving body 101 is equipped with a hydraulic pump 110 and a hydraulic control device (an example of a fluid control device) 1 that controls the flow rate of hydraulic oil (fluid) discharged from the hydraulic pump 110.

[0026] The rotating body 101 includes a cab 103 on which an operator can ride, a boom 104 having one end swingably connected to the rotating body 101, an arm 105 having one end swingably connected to the other end (tip) of the boom 104 opposite the rotating body 101, a bucket 106 swingably connected to the other end (tip) of the arm 105 opposite the boom 104, and an operation unit 107 provided on the cab 103. The traveling body 102, the rotating body 101, the boom 104, the arm 105, and the bucket 106 are driven by various hydraulic actuators 111 (an example of the actuators in the claims). The hydraulic actuators 111 are driven by hydraulic oil from a hydraulic pump 110 supplied via a hydraulic control device 1.

[0027] <Hydraulic system> Fig. 2 is a schematic diagram of a hydraulic system 109 according to the first embodiment. Fig. 2 is a schematic diagram including a cross section of the hydraulic control device 1. As shown in FIG. 2, the hydraulic system 109 includes a hydraulic control device 1, a hydraulic pump 110, and a hydraulic actuator 111.

[0028] The hydraulic actuator 111 is composed of, for example, a hydraulic motor 112 for moving the running body 102 and rotating the rotating body 101, and various hydraulic cylinders (an example of the actuator in the claims) 113 for driving the boom 104, the arm 105, and the bucket 106 (see FIG. 1). Hereinafter, one hydraulic cylinder 113 will be described as a representative example among various hydraulic cylinders 113. The representative hydraulic cylinder 113 is a cylinder that drives one selected from the boom 104, the arm 105, and the bucket 106.

[0029] The hydraulic cylinder 113 has a cylinder 114, a piston rod 115 slidably provided within the cylinder 114, and a head port (an example of an actuator supply / discharge port) Hp and a rod port (an example of an actuator supply / discharge port) Rp provided in the cylinder 114. The hydraulic cylinder 113 has the head port Hp and the rod port Rp as two supply / discharge ports. The head port Hp is provided in a portion 114a on the cylinder head side of the cylinder 114. The rod port Rp is provided in a portion 114b on the piston rod 115 side of the cylinder 114.

[0030] The hydraulic pump 110 is driven by a prime mover (not shown). The hydraulic pump 110 varies the discharge amount of hydraulic oil based on an operation signal from an operation unit 107 provided in the cab 103 (see FIG. 1). The hydraulic control device 1 is also driven and controlled based on the operation signal from the operation unit 107 (see FIG. 1). In this embodiment, there are provided two hydraulic pumps 110. Hereinafter, one of the two hydraulic pumps 110 will be referred to as a "first pump 110A" and the other of the two hydraulic pumps 110 will be referred to as a "second pump 110B."

[0031] <Hydraulic control device> The hydraulic control device 1 includes various IMVs (Independent Metering Valves) 2 (hereinafter also referred to as "independent metering valves"). The various independent metering valves 2 (an example of a fluid valve in the claims) control various hydraulic cylinders 113 that drive the boom 104, the arm 105, and the bucket 106. Hereinafter, one independent metering valve 2 will be described as a representative example among various independent metering valves 2. The representative independent metering valve 2 is a valve that controls a hydraulic cylinder 113 that drives one selected from the boom 104, the arm 105, and the bucket 106.

[0032] <Independent Metering Valve (IMV)> The independent metering valve 2 mainly comprises a valve body 3 (an example of a valve body in the claims), a round rod-shaped meter-in spool 5 housed in the valve body 3, and a first meter-in solenoid proportional valve (an example of a solenoid valve) 6 and a second meter-in solenoid proportional valve (an example of a solenoid valve) 7 that move the meter-in spool 5. The independent metering valve 2 adjusts the flow rate of hydraulic oil discharged from the hydraulic pump 110 by moving the meter-in spool 5, and causes the hydraulic oil to flow to the hydraulic cylinder 113.

[0033] Moreover, the independent metering valve 2 mainly comprises a round rod-shaped meter-out spool 15 (an example of a spool in the claims) housed in the valve body 3, a first meter-out solenoid proportional valve (an example of a solenoid valve in the claims) 16 which moves the meter-out spool 15, and a second meter-out solenoid proportional valve (an example of a solenoid valve in the claims) 17.

[0034] The independent metering valve 2 also includes a control unit 25 that controls the solenoid proportional valves 6, 7, 16, and 17. The control unit 25 is realized by a processor such as a CPU (Central Processing Unit) executing a program stored in a program memory. The control unit 25 may be realized by hardware such as an LSI (Large Scale Integration), an ASIC (Application Specific Integrated Circuit), or an FPGA (Field-Programmable Gate Array), or may be realized by a combination of software and hardware.

[0035] The valve body 3 has a first spool hole 10 that houses the meter-in spool 5, a first pump port P1 (an example of a parallel flow path in the claims) connected to the first spool hole 10, a second pump port P2 (an example of a parallel flow path in the claims), a first supply port S1 and a second supply port S2, a second spool hole 20 (an example of a spool hole in the claims) that houses the meter-out spool 15, and a first tank port T1, a second tank port T2, a first discharge port D1 (an example of a discharge port in the claims) and a second discharge port D2 (an example of a discharge port in the claims) connected to the second spool hole 20. The valve body 3 and the meter-in spool 5 are an example of the configuration of a fluid system in the claims. Here, the flow path means a path through which a fluid flows. The flow path includes not only a path having a length along the direction of flow, but also an inlet such as a pump port.

[0036] The valve body 3 also has a bridge flow passage 30 having an inverted U-shape in cross section, a first rod flow passage 31 located on one side of the bridge flow passage 30, a second rod flow passage 32 connected to the first rod flow passage 31, a first head flow passage 33 located on the other side of the bridge flow passage 30, a second head flow passage 34 connected to the first head flow passage 33, a first tank flow passage 35 located on the side of the first rod flow passage 31, a second tank flow passage 36 located on the side of the second rod flow passage 32, and a bypass flow passage 37 having a U-shape in cross section (an example of a regeneration flow passage in the claims).

[0037] The first spool hole 10 and the second spool hole 20 are formed in one direction (i.e., the axial direction of the meter-in spool 5 and the meter-out spool 15) in the valve body 3. The first spool hole 10 and the second spool hole 20 have a circular cross section along the axial direction. The first spool hole 10 and the second spool hole 20 are formed in parallel, for example, spaced apart in a direction perpendicular to the longitudinal direction (i.e., the axial direction) of each spool hole 10, 20.

[0038] The first pump port P1 is connected to the first pump 110A via a first supply flow passage 131. The first pump port P1 is a flow passage that enables hydraulic oil from the first pump 110A to be supplied to a plurality of hydraulic actuators 111. The second pump port P2 is connected to the second pump 110B via a second supply flow path 132. The second pump port P2 is a flow path that enables the hydraulic oil from the second pump 110B to be supplied to a plurality of hydraulic actuators 111. The first supply port S1 is connected to the bridge channel 30 via a first check valve 41. The second supply port S2 is connected to the bridge channel 30 via a second check valve .

[0039] The first tank port T1 is connected to the tank 120 via a first discharge flow path 135. The second tank port T2 is connected to the tank 120 via a second discharge flow path 136. The first discharge port D1 is connected to the rod port Rp via the rod flow paths 31, 32 and the rod side flow path 134. The second discharge port D2 is connected to the head port Hp via the head flow paths 33, 34 and the head side flow path 133.

[0040] Both ends of the bridge passage 30 are connected to the first spool hole 10. Both ends of the bridge passage 30 are disposed outwardly of the first supply port S1 and the second supply port S2 in the axial direction.

[0041] The first rod flow path 31 is disposed between one end of the bridge flow path 30 and the first tank flow path 35 in the axial direction. The first rod flow path 31 extends in a direction perpendicular to the axial direction. The direction perpendicular to the axial direction corresponds to the up-down direction on the paper surface of FIG. 2. The first rod flow path 31 is connected to the first tank flow path 35 via a first relief valve 45 for releasing excessive high pressure. The second rod flow path 32 is disposed between the first spool hole 10 and the second spool hole 20. The second rod flow path 32 is disposed on an extension line of the first rod flow path 31.

[0042] The first head flow path 33 is disposed between the other end of the bridge flow path 30 and the second tank flow path 36 in the axial direction. The first head flow path 33 extends in a direction intersecting the axial direction. The first head flow path 33 is connected to the second tank flow path 36 via a second relief valve 46 for releasing excessive high pressure. The first head flow path 33 is provided with a lock valve 47 (a retention valve for suppressing the boom from lowering due to inertia) for reducing leakage. The second head flow passage 34 is disposed between the first spool hole 10 and the second spool hole 20. The second head flow passage 34 extends in a direction perpendicular to the axial direction.

[0043] The first tank flow passage 35 extends outside the first rod flow passage 31 in a direction perpendicular to the axial direction. The second tank flow path 36 extends outside the first head flow path 33 in a direction perpendicular to the axial direction.

[0044] Both ends of the bypass passage 37 are connected to the second spool hole 20. The bypass passage 37 is connected to the first bypass port G1 and the second bypass port G2 via a third check valve 43 and a fourth check valve 44, respectively.

[0045] A first positioning mechanism 50 is provided at one axial end of the valve body 3. The first positioning mechanism 50 includes a first casing 51 attached to one axial end of the valve body 3 so as to close one end of each of the first spool hole 10 and the second spool hole 20. The first casing 51 has a first accommodating chamber 53 connected to one end of the first spool hole 10 and accommodating a first coil spring 52, and a second accommodating chamber 55 connected to one end of the second spool hole 20 and accommodating a second coil spring 54. The first casing 51 also has a first pump flow passage 56 extending in a direction perpendicular to the axial direction outside the first accommodating chamber 53 and the second accommodating chamber 55, and a first drain flow passage 57 extending in a direction perpendicular to the axial direction outside the first pump flow passage 56.

[0046] A second positioning mechanism 60 is provided at the other axial end of the valve body 3. The second positioning mechanism 60 includes a second casing 61 attached to the other axial end of the valve body 3 so as to close the other ends of the first spool hole 10 and the second spool hole 20. The second casing 61 has a third housing chamber 63 connected to the other end of the first spool hole 10 and a fourth housing chamber 65 connected to the other end of the second spool hole 20. The second casing 61 also has a second pump flow passage 66 extending in a direction perpendicular to the axial direction outside the third housing chamber 63 and the fourth housing chamber 65, and a second drain flow passage 67 extending in a direction perpendicular to the axial direction outside the second pump flow passage 66.

[0047] The meter-in spool 5 is housed in the first spool hole 10 of the valve body 3 so as to be slidable in the axial direction. The meter-in spool 5 is housed so as to be positioned at three positions: the central position in the axial direction of the first spool hole 10 (see FIG. 3), a position on one axial end side of the first spool hole 10 (see FIG. 4), and a position on the other axial end side of the first spool hole 10 (see FIG. 5). Hereinafter, the central position in the axial direction of the first spool hole 10 will be referred to as a first central position. Also, the position on one axial end side of the first spool hole 10 will be referred to as a first supply position, and the position on the other axial end side of the first spool hole 10 will be referred to as a second supply position. The first spool hole 10 and the meter-in spool 5 etc. constitute the meter-in valve 4. The meter-in valve 4 is a 4-port 3-position switching valve. The meter-in valve 4 controls the flow rate of the hydraulic oil discharged from the two pumps 110A, 110B.

[0048] The meter-in spool 5 has, for example, a plurality of recesses 5a formed in an annular shape, a plurality of lands 5b formed between the recesses 5a, and a plurality of notches 5c formed in the lands 5b. The meter-in spool 5 can block the flow passage and adjust the flow rate by using the recesses 5a, the lands 5b, the notches 5c, etc. The meter-in spool 5 also has, for example, a first meter-in flow passage 11 formed by the recesses 5a, the notches 5c, etc., and a second meter-in flow passage 12 formed by the recesses 5a, the notches 5c, etc. (see FIG. 4).

[0049] FIG. 3 is an explanatory diagram of an example of the operation of the hydraulic system 109 when the meter-in spool 5 of the first embodiment is located in the neutral position (first neutral position). As shown in FIG. 3, when the meter-in spool 5 is placed in the first neutral position, for example, the first pump port P1, the second pump port P2, the first supply port S1, and the second supply port S2 are blocked by lands 5b or the like.

[0050] 4 is an explanatory diagram of an example of the operation of the hydraulic system 109 when raising the boom in the first embodiment. As shown in FIG. 4, when the meter-in spool 5 is disposed at the first supply position, the first pump port P1 and the first supply port S1 communicate with each other through the first meter-in passage 11. The first meter-in passage 11 is a passage formed by the recess 5a, the notch 5c, etc., and is a passage along the arrow Vs1. When the meter-in spool 5 is disposed at the first supply position, the second pump port P2 and the second supply port S2 communicate with each other through the second meter-in passage 12. The second meter-in passage 12 is a passage formed by the recess 5a, the notch 5c, etc., and is a passage along the arrow Vs2. As a result, the first pump port P1 and the second pump port P2 communicate with the head port Hp via the first supply port S1 and the second supply port S2, etc., respectively. Note that communicating (communicating) means allowing hydraulic oil (i.e., fluid) to flow. For example, "the first pump port P1 and the first supply port S1 are connected by the first meter-in passage 11" means that the first pump port P1 and the first supply port S1 are connected by the first meter-in passage 11 so that hydraulic oil can flow. When the meter-in spool 5 is disposed in the first supply position, the rod port Rp communicates with the second rod flow path 32 and the like.

[0051] 5 is an explanatory diagram of an example of the operation of the hydraulic system 109 when lowering the boom in the first embodiment. 5, when the meter-in spool 5 is disposed at the second supply position, the first pump port P1 and the first supply port S1 communicate with each other through the first meter-in flow path 11. As a result, the first pump port P1 communicates with the rod port Rp via the first supply port S1, etc. Furthermore, when the meter-in spool 5 is disposed at the second supply position, the second supply port S2 is blocked by the land 5b, etc.

[0052] The meter-in spool 5 is a spool for allowing the hydraulic oil discharged from at least one of the two hydraulic pumps 110 to flow through a pump port or the like and from the head port Hp and the rod port Rp to the hydraulic cylinder 113. In addition, the meter-in spool 5 controls the amount of hydraulic oil supplied to the hydraulic cylinder 113 when the hydraulic oil is allowed to flow into the hydraulic cylinder 113.

[0053] 2, a first meter-in solenoid proportional valve 6 is provided at one axial end of the meter-in spool 5. A second meter-in solenoid proportional valve 7 is provided at the other axial end of the meter-in spool 5. The first meter-in solenoid proportional valve 6 and the second meter-in solenoid proportional valve 7 are commonly used valves, and detailed description of their configurations will be omitted.

[0054] The first meter-in solenoid proportional valve 6 and the second meter-in solenoid proportional valve 7 place the meter-in spool 5 in a first neutral position (see FIG. 3) when both the meter-in solenoid proportional valves 6, 7 are not energized. The first meter-in solenoid proportional valve 6, when energized while the second meter-in solenoid proportional valve 7 is in a non-energized state, moves the meter-in spool 5 to the first supply position (see FIG. 4). Here, the first meter-in solenoid proportional valve 6 can steplessly control (adjust) the first supply position according to (proportionally to) the "current value" of the energized electric signal. The second meter-in solenoid proportional valve 7 is energized while the first meter-in solenoid proportional valve 6 is in a non-energized state, thereby moving the meter-in spool 5 to the second supply position (see FIG. 5). Here, the second meter-in solenoid proportional valve 7 can steplessly control (adjust) the second supply position according to (proportionally to) the "current value" of the energized electric signal.

[0055] The meter-out spool 15 is housed in the second spool hole 20 of the valve body 3 so as to be slidable in the axial direction. The meter-out spool 15 is housed so as to be positioned at three positions: the central position in the axial direction of the second spool hole 20 (see FIG. 3), a position on one end side of the axial direction of the second spool hole 20 (see FIG. 5), and a position on the other end side of the second spool hole 20 in the axial direction (see FIG. 4). Hereinafter, the central position in the axial direction of the second spool hole 20 will be referred to as a second central position. Also, the position on one end side of the axial direction of the second spool hole 20 will be referred to as a first discharge position, and the position on the other end side of the axial direction of the second spool hole 20 will be referred to as a second discharge position. The second spool hole 20 and the meter-out spool 15 etc. constitute a meter-out valve 14. The meter-out valve 14 is a 4-port 3-position switching valve, similar to the meter-in valve 4. The meter-out valve 14 is an example of a fluid valve in the claims.

[0056] The meter-out spool 15 has, for example, a plurality of recesses 15a formed in an annular shape, a plurality of lands 15b formed between the recesses 15a, and a plurality of notches 15c formed in the lands 15b. The meter-out spool 15 can block the flow path and adjust the flow rate by the recesses 15a, the lands 15b, the notches 15c, etc. The meter-out spool 15 also has, for example, a first meter-out flow path 21 (an example of a flow path in the claims, see FIG. 4) formed by the recesses 15a, etc., and a second meter-out flow path 22 (an example of a flow path in the claims, see FIG. 5) formed by the recesses 15a, etc.

[0057] FIG. 3 is an explanatory diagram of an example of the operation of the hydraulic system 109 when the meter-out spool 15 of the first embodiment is located in the neutral position (second neutral position). As shown in FIG. 3, when the meter-out spool 15 is disposed in the second neutral position, for example, the first tank port T1, the second tank port T2, the first discharge port D1, the second discharge port D2, the first bypass port G1, and the second bypass port G2 are blocked by the land 15b or the like.

[0058] 5, when the meter-out spool 15 is disposed in the first discharge position, the second discharge port D2 and the second bypass port G2 communicate with each other through the second meter-out flow path 22. When the meter-in spool 5 is disposed in the first discharge position, the head port Hp communicates with the second head flow path 34, etc. As a result, the head port Hp communicates with the bypass flow path 37 via the second discharge port D2 and the second bypass port G2. In addition, when the meter-out spool 15 is disposed in the first discharge position, the first bypass port G1 communicates with the second rod flow path 32, etc. As a result, the second discharge port D2 communicates with the second rod flow path 32 via the bypass flow path 37. In addition, when the tank is placed in the first discharge position, the second tank port T2 is blocked by the land 15b or the like.

[0059] 4, when the meter-out spool 15 is disposed in the second discharge position, the first tank port T1 and the first discharge port D1 communicate with each other through the first meter-out flow path 21. As a result, the rod port Rp communicates with the first tank port T1 via the first discharge port D1. Furthermore, when the meter-out spool 15 is disposed in the second discharge position, the second discharge port D2 is blocked by the land 15b, etc.

[0060] The meter-out spool 15 is a spool for discharging the hydraulic oil inside the hydraulic cylinder 113 from the head port Hp and the rod port Rp to a tank via a tank port, etc. In addition, the meter-out spool 15 controls the amount of hydraulic oil discharged from the hydraulic cylinder 113 when discharging the hydraulic oil to the tank.

[0061] 2, a first meter-out solenoid proportional valve 16 is provided on one end side of the meter-out spool 15. A second meter-out solenoid proportional valve 17 is provided on the other end side of the meter-out spool 15. The first meter-out solenoid proportional valve 16 and the second meter-out solenoid proportional valve 17 are generally used valves, similar to the first meter-in solenoid proportional valve 6 and the second meter-in solenoid proportional valve 7, and detailed description of their configurations will be omitted.

[0062] The first meter-out solenoid proportional valve 16 and the second meter-out solenoid proportional valve 17 place the meter-out spool 15 in a second neutral position (see FIG. 3) when both the meter-out solenoid proportional valves 16, 17 are de-energized. The first meter-out solenoid proportional valve 16, when energized while the second meter-out solenoid proportional valve 17 is in a non-energized state, moves the meter-out spool 15 to the first discharge position (see FIG. 5). Here, the first meter-out solenoid proportional valve 16 can steplessly control (adjust) the first discharge position according to (proportionally to) the "current value" of the energized electric signal. The second meter-out solenoid proportional valve 17 is energized while the first meter-out solenoid proportional valve 16 is in a non-energized state, thereby moving the meter-out spool 15 to the second discharge position (see FIG. 4). Here, the second meter-out solenoid proportional valve 17 can steplessly control (adjust) the second discharge position according to (proportionally to) the "current value" of the energized electric signal.

[0063] <Function of independent metering valve> Next, the operation of the independent metering valve 2 will be described. 3, the first meter-in solenoid proportional valve 6 and the second meter-in solenoid proportional valve 7 are de-energized and the meter-in spool 5 is placed in the first neutral position. With the meter-in spool 5 in place, the first pump port P1, the second pump port P2, the first supply port S1, and the second supply port S2 are blocked.

[0064] In addition, the first meter-out solenoid proportional valve 16 and the second meter-out solenoid proportional valve 17 are de-energized, and the meter-out spool 15 is placed in the second neutral position. The placed meter-out spool 15 closes the first tank port T1, the second tank port T2, the first drain port D1, and the second drain port D2. When each of the hydraulic pumps 110A, 110B is driven by a prime mover (not shown), a predetermined flow rate of hydraulic oil is discharged from a discharge port of each of the hydraulic pumps 110A, 110B. For example, the discharged hydraulic oil may be returned to a tank via a return circuit (not shown).

[0065] As shown in Fig. 4, the meter-out spool 15 is moved in the direction of the arrow A1 to be disposed at the second discharge position. In this case, with the first meter-out solenoid proportional valve 16 in a non-energized state, the second meter-out solenoid proportional valve 17 is switched to an energized state, so that the meter-out spool 15 is moved toward the first meter-out solenoid proportional valve 16 (see Fig. 2) to be disposed at the second discharge position. By disposing the meter-out spool 15 at the second discharge position, the first tank port T1 and the first discharge port D1 are communicated with each other through the first meter-out flow path 21. As a result, the first tank port T1 is communicated with the rod port Rp via the first meter-out flow path 21 and the first discharge port D1. Meanwhile, the second discharge port D2 is closed by the meter-out spool 15.

[0066] Also, the meter-in spool 5 is moved in the direction of the arrow B1 to be disposed at the first supply position. In this case, with the second meter-in solenoid proportional valve 7 in a non-energized state, the first meter-in solenoid proportional valve 6 is switched to an energized state to move the meter-in spool 5 towards the second meter-in solenoid proportional valve 7 (see FIG. 2) to be disposed at the first supply position. By disposing the meter-in spool 5 at the first supply position, the first pump port P1 and the first supply port S1 are communicated with each other through the first meter-in flow path 11. Also, by disposing the meter-in spool 5 at the first supply position, the second pump port P2 and the second supply port S2 are communicated with each other through the second meter-in flow path 12. As a result, the first pump port P1 is communicated with the head port Hp via the first meter-in flow path 11 and the first supply port S1, and the second pump port P2 is communicated with the head port Hp via the second meter-in flow path 12 and the second supply port S2, etc.

[0067] Specifically, the first pump port P1 communicates with the head port Hp via the first meter-in passage 11, the first supply port S1, the first check valve 71, a part of the bridge passage 30, the first head passage 33, and the head side passage 133, while the second pump port P2 communicates with the head port Hp via the second meter-in passage 12, the second supply port S2, the second check valve 72, a part of the bridge passage 30, the first head passage 33, and the head side passage 133. By placing the meter-in spool 5 in the first supply position, the rod port Rp is communicated with the second rod flow path 32 and the like.

[0068] In this state, hydraulic oil on the piston rod 115 side of the cylinder 114 is discharged (returned) to the tank 120 as indicated by arrow Vd1 via the rod port Rp, the first discharge port D1, the first meter-out flow path 21, and the first tank port T1. Specifically, hydraulic oil on the piston rod 115 side of the cylinder 114 is discharged to the tank 120 as indicated by arrow Vd1 via the rod port Rp, the rod-side flow path 134, the first rod flow path 31, the second rod flow path 32, the first discharge port D1, the first meter-out flow path 21, the first tank port T1, and the first discharge flow path 135. In this embodiment, when the boom is raised, the hydraulic oil from the first discharge port D1 is returned to the tank 120.

[0069] Meanwhile, the hydraulic oil discharged from the discharge port of the first pump 110A flows through the first pump port P1, the first meter-in flow path 11, the first supply port S1, and the head port Hp, and then flows into the cylinder head side of the cylinder 114, as indicated by the arrow Vs1. Specifically, the hydraulic oil discharged from the discharge port of the first pump 110A flows into the cylinder head side of the cylinder 114, as indicated by the arrow Vs1, and then flows into the cylinder head side of the cylinder 114, as indicated by the arrow Vs1, and then flows into the cylinder supply flow path 131, the first pump port P1, the first meter-in flow path 11, the first supply port S1, the first check valve 71, a part of the bridge flow path 30, the first head flow path 33, the head-side flow path 133, and the head port Hp. Moreover, the hydraulic oil discharged from the discharge port of the second pump 110B passes through the second pump port P2, the second meter-in flow path 12, the second supply port S2, and the head port Hp, and flows into the cylinder head side of the cylinder 114, as indicated by the arrow Vs2. Specifically, the hydraulic oil discharged from the discharge port of the second pump 110B passes through the second supply flow path 132, the second pump port P2, the second meter-in flow path 12, the second supply port S2, the second check valve 72, a part of the bridge flow path 30, the first head flow path 33, the head-side flow path 133, and the head port Hp, and flows into the cylinder head side of the cylinder 114, as indicated by the arrow Vs2. In the hydraulic system 109 of this embodiment, when the inertial load is equal to or greater than a threshold value, such as when raising a boom, the hydraulic oil from the two pump ports P1, P2 joins together and is made to flow from the meter-in valve 4.

[0070] That is, when the meter-in spool 5 is moved in the direction of the arrow B1 (one direction), the hydraulic oil from the two pumps 110A, 110B passes through the two pump ports P1, P2 and flows together from the meter-in valve 4. The hydraulic oil discharged from the two pumps 110A, 110B joins together via the two pump ports P1, P2, the two meter-in flow paths 11, 12, the first head flow path 33, etc., and flows from the meter-in valve 4 to the cylinder head side of the hydraulic cylinder 113. As a result, the piston rod 115 of the hydraulic cylinder 113 is pushed out so as to protrude from the cylinder 114 as indicated by an arrow E1.

[0071] As shown in FIG. 5, the meter-out spool 15 is moved in the direction of the arrow A2 (one example of one-way movement of the meter-out spool in the claims) to be disposed at the first discharge position. In this case, the second meter-out solenoid proportional valve 17 is switched to a non-energized state, and the first meter-out solenoid proportional valve 16 is switched to an energized state, so that the meter-out spool 15 is moved toward the second meter-out solenoid proportional valve 17 (see FIG. 2) side and disposed at the first discharge position. By disposing the meter-out spool 15 at the first discharge position, the second discharge port D2 and the second bypass port G2 are communicated by the second meter-out flow path 22. As a result, the second bypass port G2 is communicated with the head port Hp via the second meter-out flow path 22 and the second discharge port D2. Meanwhile, the first discharge port D1, the first tank port T1, and the second tank port T2 are blocked by the meter-out spool 15. Moreover, by disposing the meter-out spool 15 in the first discharge position, the first bypass port G1 is communicated with the second rod flow path 32, etc. As a result, the second discharge port D2 is communicated with the second rod flow path 32 via the bypass flow path 37.

[0072] Also, the meter-in spool 5 is moved in the direction of arrow B2 to be disposed in the second supply position. In this case, the first meter-in solenoid proportional valve 6 is switched to a non-energized state, and the second meter-in solenoid proportional valve 7 is switched to an energized state, thereby moving the meter-in spool 5 toward the first meter-in solenoid proportional valve 6 (see FIG. 2) and disposing it in the second supply position. By disposing the meter-in spool 5 in the second supply position, the first pump port P1 and the first supply port S1 are communicated with each other through the first meter-in flow path 11. As a result, the first pump port P1 is communicated with the rod port Rp via the first meter-in flow path 11 and the first supply port S1. Meanwhile, the second supply port S2 is blocked by the meter-in spool 5.

[0073] Specifically, the first pump port P1 communicates with the rod port Rp via the first meter-in passage 11, the first supply port S1, the first check valve 71, a part of the bridge passage 30, the first rod passage 31, and the rod side passage .

[0074] In this state, the hydraulic oil on the cylinder head side of the cylinder 114 flows through the head port Hp, the second discharge port D2, the second meter-out passage 22, the second bypass port G2, etc., toward the second rod passage 32 (an example of a regeneration passage) as indicated by the arrow Ve. Specifically, the hydraulic oil on the cylinder head side of the cylinder 114 flows through the head port Hp, the head side passage 133, the first head passage 33, the second head passage 34, the second discharge port D2, the second meter-out passage 22, the second bypass port G2, the bypass passage 37, the third check valve 73, the first bypass port G1, the second rod passage 32, the first rod passage 31, and the rod side passage 134, toward the rod port Rp as indicated by the arrow Ve. In this embodiment, when the boom is lowered, the hydraulic oil from the second discharge port D2 is used (regenerated) to drive the hydraulic cylinder 113.

[0075] On the other hand, the hydraulic oil discharged from the discharge port of the first pump 110A flows through the first pump port P1, the first meter-in flow path 11, the first supply port S1, and the rod port Rp to the piston rod 115 side of the cylinder 114 as indicated by the arrow Vs3. Specifically, the hydraulic oil discharged from the discharge port of the first pump 110A flows through the first supply flow path 131, the first pump port P1, the first meter-in flow path 11, the first supply port S1, the first check valve 71, a part of the bridge flow path 30, the first rod flow path 31, the rod-side flow path 134, and the rod port Rp to the piston rod 115 side of the cylinder 114 as indicated by the arrow Vs3. In the hydraulic system 109 of this embodiment, when the inertial load is less than a threshold value, such as when lowering a boom, only one of the hydraulic oils from the two pump ports P1 and P2 (hydraulic oil from only one pump port P1) flows from the meter-in valve 4.

[0076] That is, when the meter-in spool 5 is moved in the direction of the arrow B2 (the other direction), hydraulic oil from only one of the two pumps 110A, 110B (only the first pump 110A) flows from the meter-in valve 4 via only one of the two pump ports P1, P2 (only the first pump port P1). The hydraulic oil discharged from the first pump 110A flows from the meter-in valve 4 to the piston rod 115 side of the hydraulic cylinder 113 via the first pump port P1, the first meter-in flow path 11, the first rod flow path 31, etc. In addition, when the meter-out spool 15 is moved in the direction of the arrow A2, hydraulic oil from the second discharge port D2 flows from the meter-out valve 14 to the piston rod 115 side of the hydraulic cylinder 113. As a result, the piston rod 115 of the hydraulic cylinder 113 is retracted so as to be pushed into the cylinder 114 as indicated by an arrow E2.

[0077] In this way, the independent metering valve 2 is provided with the meter-in spool 5 and the meter-out spool 15. The piston rod 115 can be moved in two directions, the directions of arrows E1 and E2, by controlling the drive of the meter-in spool 5 and the meter-out spool 15. In this way, the spool that switches the movement of the piston rod 115 in the two directions can be divided into the meter-in spool 5 and the meter-out spool 15.

[0078] In addition, the meter-in spool 5 is driven and controlled to a first supply position by the first meter-in solenoid proportional valve 6, and the meter-out spool 15 is driven and controlled to a second discharge position by the second meter-out solenoid proportional valve 17. This allows the piston rod 115 of the hydraulic cylinder 113 to move in the direction of the arrow E1 (one direction). Furthermore, the meter-in spool 5 is driven and controlled to the second supply position by the second meter-in solenoid proportional valve 7, and the meter-out spool 15 is driven and controlled to the first discharge position by the first meter-out solenoid proportional valve 16. This allows the piston rod 115 of the hydraulic cylinder 113 to move in the direction of the arrow E2 (the other direction).

[0079] Therefore, the drive control of the meter-in spool 5 and the meter-out spool 15 can be electrically and individually adjusted by the first meter-in solenoid proportional valve 6, the second meter-in solenoid proportional valve 7, the first meter-out solenoid proportional valve 16, and the second meter-out solenoid proportional valve 17. In other words, the meter-in spool 5 and the meter-out spool 15 can form the independent metering valve 2. As a result, when adjusting the independent metering valve 2 (i.e., the hydraulic control device 1) in an actual machine to suit the application of, for example, construction machinery, the drive control of the meter-in spool 5 and the meter-out spool 15 can be individually adjusted. This makes it easy to adjust the actual machine, and the adjustment period can be shortened.

[0080] Here, the first meter-in solenoid proportional valve 6 can adjust the first supply position steplessly in proportion to the "current value" of the electric signal applied. The second meter-in solenoid proportional valve 7 can adjust the second supply position steplessly in proportion to the "current value" of the electric signal applied. Furthermore, the first meter-out solenoid proportional valve 16 can adjust the first discharge position steplessly in proportion to the "current value" of the electric signal applied. The second meter-out solenoid proportional valve 17 can adjust the second discharge position steplessly in proportion to the "current value" of the electric signal applied. Therefore, when adjusting the independent metering valve 2 (hydraulic control device 1) in accordance with the application of a construction machine or the like, the drive control of the meter-in spool 5 and the meter-out spool 15 can be adjusted steplessly. This makes it easier to adjust the actual machine, and shortens the adjustment period.

[0081] Also, the meter-in spool 5 and the meter-out spool 15 are driven and controlled by the first meter-in solenoid proportional valve 6, the second meter-in solenoid proportional valve 7, the first meter-out solenoid proportional valve 16, and the second meter-out solenoid proportional valve 17. This makes it possible to electrically adjust the drive control of the meter-in spool 5 and the meter-out spool 15, making it possible to respond to markets where electrification is expected in the future and increasing versatility.

[0082] The hydraulic control device 1 of the present embodiment is configured to include one each of the meter-in spool 5 and the meter-out spool 15, so that the piston rod 115 of the hydraulic cylinder 113 can be switched in two directions. Therefore, one each of the meter-in spool 5 and the meter-out spool 15 can be used to switch the piston rod 115 in two directions. Therefore, it is not necessary to provide, for example, two each of the meter-in spools and the meter-out spools in order to switch the piston rod 115 in two directions. This makes it possible to simplify the circuit configuration of the independent metering valve 2 (i.e., the meter-in spool, the meter-out spool).

[0083] 1, a construction machine 100 has a hydraulic control device 1 equipped with an independent metering valve 2 mounted on a rotating body 101. With this configuration, when adjusting the hydraulic control device 1 to suit the application of the construction machine 100, the drive control of the meter-in spool 5 and the meter-out spool 15 can be adjusted individually, thereby shortening the adjustment period.

[0084] As described above, the construction machine 100 according to this embodiment includes the boom 104, the pumps 110A and 110B that discharge hydraulic oil, the hydraulic control device 1 having the independent metering valve 2 that controls the flow rate of the hydraulic oil discharged from the pumps 110A and 110B, and the hydraulic cylinder 113 through which the hydraulic oil whose flow rate is controlled by the independent metering valve 2 flows to drive the boom 104. The independent metering valve 2 includes a valve body 3 having a first spool hole 10, a second spool hole 20, and discharge ports D1 and D2 connected to the second spool hole 20, a meter-in spool 5 that is movably provided in the first spool hole 10 and controls the amount of hydraulic oil supplied to the hydraulic cylinder 113, and a meter-out spool 15 that is movably provided in the second spool hole 20 and controls the amount of hydraulic oil discharged from the hydraulic cylinder 113. The hydraulic control device 1 includes solenoid valves 16 and 17 that move the meter-out spool 15, and a control unit 25 that controls the solenoid valves 16 and 17. In the independent metering valve 2, when the meter-out spool 15 is moved in the direction of the arrow A2 (one direction), the second discharge port D2 is connected to the bypass flow path 37. The meter-out spool 15 has a notch 15c and a land 15b that can block the flow path and adjust the flow rate.

[0085] According to this configuration, the second discharge port D2 is connected to the bypass flow path 37 by moving the meter-out spool 15 in the direction of the arrow A2 (one direction), so that the hydraulic oil from the second discharge port D2 can be used (regenerated) to drive the hydraulic cylinder 113, thereby achieving energy savings with a simple configuration. In addition, the independent metering valve 2 is equipped with a meter-in spool 5 that controls the amount of hydraulic oil supplied to the hydraulic cylinder 113, making it possible to easily adjust the amount of hydraulic oil supplied to the hydraulic cylinder 113 in accordance with fluctuations in the load on the hydraulic cylinder 113. In addition, the independent metering valve 2 is equipped with a meter-out spool 15 that controls the amount of hydraulic oil discharged from the hydraulic cylinder 113, making it possible to easily adjust the amount of hydraulic oil discharged from the hydraulic cylinder 113 in accordance with fluctuations in the load on the hydraulic cylinder 113. In addition, the hydraulic control device 1 is equipped with solenoid valves 16, 17 that move the meter-out spool 15 and a control unit 25 that controls the solenoid valves 16, 17, so that the drive control of the meter-out spool 15 can be electrically adjusted, thereby simplifying the circuit configuration. In addition, the meter-out spool 15 has the notch 15c and the land 15b that can block the flow path and adjust the flow rate, so that the flow path can be blocked and the flow rate can be adjusted with a simple structure.

[0086] The control method of this embodiment includes an ascent process for raising the boom 104 and a descent process for lowering the boom 104. During the ascent process, the meter-out spool 15 is moved in the direction of arrow A1 (other direction) to return the hydraulic oil from the first discharge port D1 to the tank 120, and during the descent process, the meter-out spool 15 is moved in the direction of arrow A2 (one direction) to regenerate the hydraulic oil from the second discharge port D2. According to this method, during the lowering process, the hydraulic oil from the second discharge port D2 can be regenerated and used (regenerated) to drive the hydraulic cylinder 113 during the lowering operation of the boom 104, thereby saving energy.

[0087] In the above-described embodiment, an example in which two hydraulic pumps 110 and two tanks 120 are provided has been described, but this is not limiting. For example, one hydraulic pump 110 and one tank 120 may be provided, or three or more of each may be provided. For example, the number of hydraulic pumps 110 and tanks 120 provided can be changed according to required specifications.

[0088] In the above-described embodiment, an example in which the hydraulic oil is regenerated by part of the hydraulic oil from the second discharge port D2 flowing into the bypass flow passage 37 has been described, but the present invention is not limited thereto. For example, the hydraulic oil may be regenerated by part of the hydraulic oil from the second discharge port D2 flowing into the bridge flow passage 30. For example, the hydraulic oil may be regenerated by part of the hydraulic oil from the second discharge port D2 flowing into the hydraulic pump 110. For example, the hydraulic oil may be regenerated by part of the hydraulic oil from the second discharge port D2 flowing into the hydraulic cylinder 113 without passing through the bypass flow passage 37 or the like. For example, the hydraulic oil may be regenerated by all of the hydraulic oil from the second discharge port D2 flowing into the bypass flow passage 37. For example, the hydraulic oil from the second discharge port D2 may be regenerated by all of the hydraulic oil flowing into the second discharge flow passage 136. For example, the meter-out spool 15 may be further moved in the direction of the arrow A2 from the first discharge position shown in FIG. 5 to block the second discharge port D2 and the second bypass port G2 with the meter-out spool 15, and the second discharge port D2 and the second tank port T2 may be connected. That is, it is only necessary that the discharge port connected to the second spool hole 20 is connected to at least one of the regeneration flow path and the tank flow path.

[0089] In the above-described embodiment, an example has been described in which the regeneration flow passage 37 regenerates hydraulic oil to the second rod flow passage 32, but this is not limited thereto. For example, the regeneration flow passage 37 may be a flow passage that regenerates hydraulic oil to the head flow passages 33 and 34.

[0090] <Second embodiment> 6 is an explanatory diagram of an example of the operation of the hydraulic system 209 when lowering the boom in the second embodiment. In the above-described first embodiment, an example has been described in which a portion of the hydraulic oil from the second discharge port D2 flows toward the rod port Rp when the boom is lowered, but this is not limiting. For example, a portion of the hydraulic oil from the second discharge port D2 may flow toward the first spool hole 10 (the flow path of the meter-in valve 4) when the boom is lowered. In FIG. 6, the same components as those in the above-described first embodiment are denoted by the same reference numerals, and detailed description thereof will be omitted. Reference numeral 238 in FIG. 6 indicates an intermediate flow path connecting the first spool hole 10 and the second spool hole 20.

[0091] As shown in FIG. 6, in the hydraulic system 209 of this embodiment, when the boom is lowered, a part of the hydraulic oil from the second discharge port D2 flows toward the first spool hole 10. Specifically, a part of the hydraulic oil from the second discharge port D2 flows toward the first pump port P1 connected to the first spool hole 10 as indicated by the arrow Ve2 via the second meter-out passage 22, the bypass passage 37, the third check valve 73, and the intermediate passage 238. The first pump port P1 is a parallel passage that can supply hydraulic oil to other hydraulic actuators different from the boom. In this embodiment, when the boom is lowered, a part of the hydraulic oil from the second discharge port D2 is guided to the first pump port P1 and used (regenerated) for driving the other hydraulic actuator. For example, the hydraulic oil flowing to the first pump port P1 can be used for driving the hydraulic pump 110, the hydraulic cylinder 113, and the like.

[0092] A portion of the hydraulic oil flowing through the intermediate passage 238 may be branched off from the intermediate passage 238 as indicated by the arrow Ve3 and flow toward the first spool hole 10. Alternatively, all of the hydraulic oil flowing through the intermediate passage 238 may be branched off from the intermediate passage 238 as indicated by the arrow Ve3 and flow toward the first spool hole 10.

[0093] According to this configuration, the second discharge port D2 is connected to the first spool hole 10 by moving the meter-out spool 15 in the direction of arrow A2 (one direction), so that the hydraulic oil from the second discharge port D2 can be used (regenerated) to drive the meter-in valve 4, thereby achieving energy savings with a simple configuration.

[0094] For example, all of the hydraulic oil from the second drain port D2 may flow into the second drain passage 136. For example, by further moving the meter-out spool 15 in the direction of arrow A2 from the position shown in Fig. 6, the second drain port D2 and the second bypass port G2 may be blocked by the meter-out spool 15, and the second drain port D2 and the second tank port T2 may be connected. That is, it is only necessary that the drain port connected to the second spool hole 20 is connected to at least one of the regeneration passage and the tank passage.

[0095] <Third embodiment> 7 is an explanatory diagram of an example of the operation of the hydraulic system 309 when driving the actuator of the third embodiment. In the above-described first embodiment, an example of the operation of the hydraulic system when raising and lowering the boom has been described, but the present invention is not limited to this. For example, the present invention may be applied to the operation of the hydraulic system when pulling and pushing an arm. In Fig. 7, the same components as those in the above-described first embodiment are given the same reference numerals, and detailed description thereof will be omitted.

[0096] As shown in FIG. 7, a hydraulic system 309 of this embodiment includes one hydraulic pump 310, three tanks 320A-320C, a meter-in spool 5 (meter-in valve 4), a meter-out spool 15 (meter-out valve 14), and two hydraulic cylinders 313A and 313B. Hereinafter, one of the two hydraulic cylinders 313A and 313B will be referred to as the "first cylinder 313A" and the other as the "second cylinder 313B." The first cylinder 313A is an example of an actuator for driving a boom. The second cylinder 313B is an example of an actuator for driving an arm. The second cylinder 313B is an example of another actuator different from the actuator for driving a boom in the claims.

[0097] In the hydraulic system 309 of this embodiment, when the boom is lowered and the arm is pushed, hydraulic oil is discharged from one hydraulic pump 310, and flows toward the first cylinder 313A as indicated by arrow Vc1 due to the movement of the meter-in spool 5 in the direction of arrow C11. A part of the hydraulic oil flowing from the first cylinder 313A toward the tank 320A flows toward the second cylinder 313B as indicated by arrow Vc2 via the parallel flow path 339, the regeneration flow path (flow path along arrow Vr), and the discharge port (not shown) of the meter-out valve 14 due to the movement of the meter-out spool 15 in the direction of arrow C12 (one direction). The hydraulic oil discharged from one pump 310 flows toward the piston rods 115 of the first cylinder 313A and the second cylinder 313B. Therefore, the piston rods 115 of the first cylinder 313A and the second cylinder 313B are retracted as indicated by arrows Ea and Eb so as to be pushed into the cylinder 114. In this embodiment, when the boom is lowered and the arm is pushed, a portion of the hydraulic oil flowing from the first cylinder 313A toward the tank 320A is used (regenerated) to drive the second cylinder 313B.

[0098] According to this configuration, the movement of the meter-out spool 15 in the direction of arrow C12 (one direction) connects the discharge port of the meter-out valve 14 to the second cylinder 313B, so that the hydraulic oil from the discharge port of the meter-out valve 14 can be used (regenerated) to drive the second cylinder 313B, thereby achieving energy conservation with a simple configuration.

[0099] The technical scope of the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the spirit of the present invention.

[0100] For example, in the above embodiment, the construction machine 1 is a hydraulic excavator, but the present invention is not limited to this. For example, the present invention may be applied to construction machines other than hydraulic excavators, such as hydraulic cranes.

[0101] In the above-described embodiment, the fluid system is a hydraulic system equipped with a hydraulic control device, but the present invention is not limited to this. For example, the fluid system may be equipped with a fluid control device other than a hydraulic control device, such as an air pressure control device or a water pressure control device.

[0102] In the above-described embodiment, an example has been described in which the fluid system includes a pump, a fluid control device, and an actuator, but the present invention is not limited thereto. For example, the fluid system may include a fluid control device and an actuator without including a pump. For example, the fluid system may include a pump and a fluid control device without including an actuator.

[0103] In the above embodiment, the hydraulic cylinder 113 has been described as an example of an actuator, but the present invention is not limited to this. For example, the present invention may be applied to an actuator such as a hydraulic motor.

[0104] In the above-described embodiment, the solenoid valves are the proportional solenoid valves 6, 7, 16, and 17. However, the present invention is not limited to this. For example, the present invention may be applied to various solenoid valves that are driven based on an electric signal.

[0105] In addition, the components in the above-described embodiment may be replaced with well-known components without departing from the spirit of the present invention. Also, the above-described modified examples may be combined. [Explanation of symbols]

[0106] 1...Hydraulic control device (fluid control device) 2...Independent metering valve (fluid valve) 3...Valve body 4. Meter-in valve 5…Meter-in spool 10…First spool hole 14...Meter-out valve (fluid valve) 15...Meter out spool 15b…Land 15c...notch 16...First meter-out solenoid proportional valve (solenoid valve) 17...Second meter-out solenoid proportional valve (solenoid valve) 20...Second spool hole (spool hole) 21...First meter-out passage (passage) 22...Second meter-out flow path (flow path) 25...Control section 37...Bypass flow path (regeneration flow path) 100...Hydraulic excavator (construction machinery) 104…Boom 109, 209, 309...Hydraulic systems (fluid systems) 113...Hydraulic cylinder (actuator) 120, 320A, 320B, 320C...Tank 120A…First tank (tank) 120B…Second tank (tank) 313A…First cylinder (actuator) 313B…Second cylinder (other actuator) 339…Parallel flow path A2…One-way movement of the meter-out spool D1…First exhaust port (exhaust port) D2: Second exhaust port (exhaust port)

Claims

1. A pump that discharges a fluid; A fluid control device having a fluid valve that controls the flow rate of the fluid discharged from the pump to flow to the actuator, The fluid valve includes: a valve body having a first spool bore, a second spool bore, and a discharge port connected to the second spool bore; a meter-in spool movably provided in the first spool hole; a meter-out spool movably provided in the second spool hole, The fluid control device further includes a first solenoid valve and a second solenoid valve that move the meter-in spool and the meter-out spool, respectively, and a control unit that controls the first solenoid valve and the second solenoid valve, When the meter-out spool is moved in one direction, the discharge port is connected to at least one of the regeneration flow path and the tank flow path, the discharge port is a port that communicates with a head port or a rod port of a cylinder that constitutes the actuator and discharges fluid from the head port or the rod port to a tank, The regeneration flow path is a flow path for utilizing the fluid from the head port or the rod port to drive the pump or the actuator. Fluid systems.

2. Boom and A pump that discharges a fluid; a fluid control device having a fluid valve that controls the flow rate of the fluid discharged from the pump; an actuator for driving the boom by flowing the fluid whose flow rate is controlled by the fluid valve, The fluid valve includes: a valve body having a first spool bore, a second spool bore, and a discharge port connected to the second spool bore; a meter-in spool that is movably disposed in the first spool hole and controls the amount of fluid supplied to the actuator; a meter-out spool that is movably provided in the second spool hole and controls the amount of fluid discharged from the actuator, The fluid control device further includes a solenoid valve that moves the meter-out spool, and a control unit that controls the solenoid valve, When the meter-out spool is moved in one direction, the discharge port is connected to the regeneration flow path, the discharge port is a port that communicates with a head port or a rod port of a cylinder that constitutes the actuator and discharges fluid from the head port or the rod port to a tank, The regeneration flow path is a flow path for utilizing the fluid from the head port or the rod port to drive the pump or the actuator. Construction machinery.

3. Boom and A pump that discharges a fluid; a fluid control device having a fluid valve that controls the flow rate of the fluid discharged from the pump; an actuator for driving the boom by flowing the fluid whose flow rate is controlled by the fluid valve, The fluid valve includes: a valve body having a first spool bore, a second spool bore, and a discharge port connected to the second spool bore; a meter-in spool that is movably disposed in the first spool hole and controls the amount of fluid supplied to the actuator; a meter-out spool that is movably provided in the second spool hole and controls the amount of fluid discharged from the actuator, The fluid control device further includes a solenoid valve that moves the meter-out spool, and a control unit that controls the solenoid valve, When the meter-out spool is moved in one direction, the discharge port is connected to the first spool hole, The discharge port is a port that communicates with a head port or a rod port of a cylinder that constitutes the actuator, and that discharges fluid from the head port or the rod port to a tank. Construction machinery.

4. Boom and A pump that discharges a fluid; a fluid control device having a fluid valve that controls the flow rate of the fluid discharged from the pump; an actuator for driving the boom by flowing the fluid whose flow rate is controlled by the fluid valve, The fluid valve includes: a valve body having a first spool bore, a second spool bore, and a discharge port connected to the second spool bore; a meter-in spool that is movably disposed in the first spool hole and controls the amount of fluid supplied to the actuator; a meter-out spool that is movably provided in the second spool hole and controls the amount of fluid discharged from the actuator, The fluid control device further includes a solenoid valve that moves the meter-out spool, and a control unit that controls the solenoid valve, When the meter-out spool is moved in one direction, the discharge port is connected to another actuator different from the actuator, The discharge port is a port that communicates with a head port or a rod port of a cylinder that constitutes the actuator, and that discharges fluid from the head port or the rod port to a tank. Construction machinery.

5. A method for controlling a construction machine comprising: a boom; a pump for discharging a fluid; a fluid valve for controlling the flow rate of the fluid discharged from the pump; and an actuator for driving the boom by flowing the fluid flow-controlled by the fluid valve, wherein the fluid valve comprises a valve body having a first spool hole, a second spool hole, and a first discharge port and a second discharge port connected to the second spool hole; a meter-in spool movably provided in the first spool hole for controlling the amount of fluid supplied to the actuator; and a meter-out spool movably provided in the second spool hole for controlling the amount of fluid discharged from the actuator, a raising step of raising the boom; a lowering step of lowering the boom, the first discharge port is a port that communicates with a rod port of a cylinder that constitutes the actuator and discharges fluid from the rod port to a tank, the second exhaust port is a port separate from the first exhaust port and communicates with a head port of the cylinder, In the rising process, the meter-out spool is moved in one direction to return the fluid from the first discharge port to a tank, In the lowering step, the meter-out spool is moved in the other direction to reclaim the fluid from the second discharge port. Control methods.

Images