JP7508337B2 - Fluid systems and construction machinery - Google Patents

Description

The present invention relates to a fluid valve, a fluid system, a construction machine, and a control method.

For example, construction machinery such as hydraulic excavators 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.

JP 2004-360751 A

However, it is desirable to merge and flow fluids from two flow paths by moving the spool in one direction.

The present invention has been made to solve the above problems, and aims to provide a fluid valve, a fluid system, a construction machine, and a control method that can merge and flow fluids from two flow paths by moving a spool in one direction.

( 1 ) A fluid system according to an aspect of the present invention is a fluid system comprising at least two pumps that discharge fluid, and a fluid control device having a fluid valve that controls the flow rate of the fluid discharged from the two pumps and flows the fluid to an actuator, wherein the fluid valve comprises a valve body having a first spool hole and a second spool hole and two flow paths connected to the first 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 when the meter-in spool is moved in one direction, fluids from the two flow paths are merged to flow to the actuator.

With this configuration, fluids from two flow paths can be merged and flowed by moving the spool in one direction.

( 2 ) A construction machine according to an aspect of the present invention is a construction machine comprising: a boom; two pumps that discharge fluid; a fluid control device having fluid valves that control the flow rate of the fluid discharged from the two pumps; and an actuator for driving the boom by flowing the fluid flow-controlled by the fluid valves, wherein the fluid valve comprises a valve body having a first spool hole and a second spool hole and two flow paths connected to the first 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 when the meter-in spool is moved in one direction, fluids from the two flow paths are merged to flow to the actuator, and when the meter-in spool is moved in the other direction, only one of the fluids from the two flow paths is flowed.

According to this configuration, the fluid from the two flow paths can be merged by moving the spool in one direction, and the fluid can be supplied to the actuator. For example, the amount of fluid supplied to the actuator can be easily adjusted in response to fluctuations in the load on the actuator.
In addition, by moving the spool in the other direction, only one of the two fluid paths is allowed to flow, resulting in a minimum required output, which contributes to energy conservation. For example, the raising and lowering of a boom can be performed with less energy.
In addition, by including a solenoid valve that moves the spool and a control unit that controls the solenoid valve, the fluid control device can electrically adjust the drive control of the spool, thereby simplifying the circuit configuration.

( 3 ) A construction machine according to an aspect of the present invention is a construction machine comprising: an arm, two pumps that discharge fluid, a fluid control device having fluid valves that control the flow rate of the fluid discharged from the two pumps, and an actuator to drive the arm by flowing the fluid flow-controlled by the fluid valves, wherein the fluid valve comprises a valve body having a first spool hole and a second spool hole and two flow paths connected to the first 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 the discharge flow rates of the two pumps are different, and when the meter-in spool is moved in one direction, the fluids from the two flow paths are joined together to flow to the actuator, and when the meter-in spool is moved in the other direction, the fluids from the two flow paths are joined together to flow to the actuator.

According to this configuration, the fluid from the two flow paths can be merged by moving the spool in one direction, and the fluid can be supplied to the actuator. For example, the amount of fluid supplied to the actuator can be easily adjusted in response to fluctuations in the load on the actuator.
Additionally, movement of the spool in the other direction can combine fluid from the two flow paths to provide fluid flow to the actuator.
In addition, since the discharge flow rates of the two pumps are different from each other, the discharge flow rates of the two pumps can be adjusted according to the usage status of the actuator. For example, by adjusting the discharge flow rates of the two pumps according to the driving status of the arm, energy can be saved.
In addition, by including a solenoid valve that moves the spool and a control unit that controls the solenoid valve, the fluid control device can electrically adjust the drive control of the spool, thereby simplifying the circuit configuration.

The present invention provides a fluid valve, a fluid system, a construction machine, and a control method that can merge and flow fluids from two flow paths by moving a spool in one direction.

1 is a schematic diagram of a construction machine according to a first embodiment. FIG. FIG. 1 is a schematic diagram of a hydraulic system according to a first embodiment. 5A to 5C are diagrams illustrating an example of an operation of the hydraulic system when the meter-in spool in the first embodiment is located in a neutral position. 5A to 5C are explanatory diagrams of an example of an operation of the hydraulic system when raising a boom in the first embodiment. 5A to 5C are explanatory diagrams of an example of an operation of the hydraulic system when lowering a boom in the first embodiment. 13A to 13C are explanatory diagrams of an example of an operation of the hydraulic system when pushing the arm of the second embodiment. 13A to 13C are diagrams illustrating an example of an operation of the hydraulic system when pulling the arm in the second embodiment. 13A to 13C are diagrams illustrating an example of an operation of the hydraulic system when the meter-in spool of the third embodiment is located in a neutral position. 13 is an explanatory diagram of an example of the operation of the hydraulic system when raising a boom in the third embodiment. FIG. 13A to 13C are explanatory diagrams of an example of the operation of the hydraulic system when lowering a boom in the third embodiment.

Embodiments of the present invention will be described below with reference to the drawings. In the following embodiments, a hydraulic excavator equipped with a hydraulic system (fluid system) will be used as an example of construction machinery. Note that in the drawings used in the following description, the scale of each component has been appropriately altered to ensure that each component is of a recognizable size.

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.

The rotating body 101 includes a cab 103 on which an operator can ride, a boom 104 whose one end is connected to the rotating body 101 so as to be freely swingable, an arm 105 whose one end is connected to the other end (tip) of the boom 104 opposite the rotating body 101 so as to be freely swingable, a bucket 106 whose other end (tip) of the arm 105 opposite the boom 104 so as to be freely swingable, and an operating unit 107 provided on the cab 103. The running body 102, the rotating body 101, the boom 104, the arm 105, and the bucket 106 are driven by various hydraulic actuators (an example of the actuators in the claims) 111. The hydraulic actuators 111 are driven by hydraulic oil from a hydraulic pump 110 supplied via the hydraulic control device 1.

<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 a 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 .

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 the 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.

The hydraulic cylinder 113 has a cylinder 114, a piston rod 115 provided slidably 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.

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 the embodiment, two hydraulic pumps 110 are provided. 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."

<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.

<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 (an example of a spool in the claims) housed in the valve body 3, and a first meter-in electromagnetic proportional valve (an example of a solenoid valve in the claims) 6 and a second meter-in electromagnetic proportional valve (an example of a solenoid valve in the claims) 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 flows the hydraulic oil into the hydraulic cylinder 113.

The independent metering valve 2 is mainly composed of a rod-shaped meter-out spool 15 housed in the valve body 3, and a first meter-out solenoid proportional valve 16 and a second meter-out solenoid proportional valve 17 that move the meter-out spool 15.

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 software and hardware working together.

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

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 to the side of the first rod flow passage 31, a second tank flow passage 36 located to the side of the second rod flow passage 32, and a bypass flow passage 37 having a U-shape in cross section.

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, spaced apart from each other, for example, in a direction perpendicular to the longitudinal direction (i.e., the axial direction) of each spool hole 10, 20.

The first pump port P1 is connected to the first pump 110A via the first supply flow path 131. The second pump port P2 is connected to the second pump 110B via the second supply flow path 132. The first supply port S1 is connected to the bridge flow path 30 via the first check valve 41. The second supply port S2 is connected to the bridge flow path 30 via the second check valve 42.

The first tank port T1 is connected to the tank 120 via the first discharge flow path 135. The second tank port T2 is connected to the tank 120 via the 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.

Both ends of the bridge passage 30 are connected to the first spool hole 10. Both ends of the bridge passage 30 are located axially outward of the first supply port S1 and the second supply port S2.

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.

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 preventing 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.

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

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

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 storage chamber 53 connected to one end of the first spool hole 10 and accommodating a first coil spring 52, and a second storage 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 storage chamber 53 and the second storage 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.

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 chamber 63 connected to the other end of the first spool hole 10 and a fourth 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 chamber 63 and the fourth 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.

The meter-in spool 5 is housed in a 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: a 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 constitute a meter-in valve 4. The meter-in valve 4 is a four-port three-position switching valve. The meter-in valve 4 controls the flow rate of the hydraulic oil discharged from the two pumps 110A, 110B. The meter-in valve 4 is an example of a fluid valve as defined in the claims.

The meter-in spool 5 has, for example, a number of recesses 5a formed in an annular shape, a number of lands 5b formed between the recesses 5a, and a number of notches 5c formed in the lands 5b. The meter-in spool 5 can block the flow path 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 path 11 (an example of a flow path in the claims) formed by the recesses 5a, the notches 5c, etc., and a second meter-in flow path 12 (an example of a flow path in the claims) formed by the recesses 5a, the notches 5c, etc. (see FIG. 4).

FIG. 3 is an explanatory diagram of an example of the operation of the hydraulic system 109 when the meter-in spool 5 in the first embodiment is located in the neutral position (first neutral position).
As shown in FIG. 3, when the meter-in spool 5 is disposed 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.

4 is an explanatory diagram of an example of the operation of the hydraulic system 109 when raising the boom in the first embodiment. 4 corresponds to an explanatory diagram of the action of pushing out the piston rod 115 of the hydraulic cylinder 113.
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 are communicated 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 are communicated 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 are communicated 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, "connecting the first pump port P1 and the first supply port S1 through 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.

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 corresponds to an explanatory diagram of the action of retracting the piston rod 115 of the hydraulic cylinder 113.
5, when the meter-in spool 5 is disposed in the second supply position, the first pump port P1 and the first supply port S1 communicate with each other through the first meter-in passage 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 in the second supply position, the second supply port S2 is blocked by the land 5b, etc.

The meter-in spool 5 is a spool for directing hydraulic oil discharged from at least one of the two hydraulic pumps 110 through a pump port, etc., and from the head port Hp and rod port Rp to the hydraulic cylinder 113. The meter-in spool 5 also controls the amount of hydraulic oil supplied to the hydraulic cylinder 113 when the hydraulic oil is flowing to the hydraulic cylinder 113.

As shown in FIG. 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 explanation of their configurations will be omitted.

The first meter-in electromagnetic proportional valve 6 and the second meter-in electromagnetic proportional valve 7 place the meter-in spool 5 in a first neutral position (see FIG. 3) when both the meter-in electromagnetic proportional valves 6, 7 are de-energized.
The first meter-in solenoid proportional valve 6 is energized while the second meter-in solenoid proportional valve 7 is in a non-energized state, thereby moving 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 (proportional to) the “current value” of the electrical signal energized.
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 (proportional to) the "current value" of the electrical signal energized.

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: a central position in the axial direction of the second spool hole 20 (see FIG. 3), a position on one end side of the second spool hole 20 in the axial direction (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 the meter-out valve 14. Like the meter-in valve 4, the meter-out valve 14 is a four-port three-position change-over valve.

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 using the recesses 15a, the lands 15b, the notches 15c, etc. In addition, the meter-out spool 15 has, for example, a first meter-out flow path 21 (see FIG. 4) formed by the recesses 15a, etc., and a second meter-out flow path 22 (see FIG. 5) formed by the recesses 15a, etc.

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 positioned 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 lands 15b, etc.

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.
Furthermore, 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, with the tank cap 15 placed in the first discharge position, the second tank port T2 is blocked by the land 15b or the like.

As shown in FIG. 4, when the meter-out spool 15 is positioned in the second discharge position, it connects the first tank port T1 and the first discharge port D1 through the first meter-out flow path 21. As a result, the rod port Rp is connected to the first tank port T1 via the first discharge port D1. In addition, when the meter-out spool 15 is positioned in the second discharge position, it closes the second discharge port D2 with the land 15b, etc.

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

As shown in FIG. 2, a first meter-out solenoid proportional valve 16 is provided on one end of the meter-out spool 15. A second meter-out solenoid proportional valve 17 is provided on the other end of the meter-out spool 15. The first meter-out solenoid proportional valve 16 and the second meter-out solenoid proportional valve 17 are commonly used valves, like the first meter-in solenoid proportional valve 6 and the second meter-in solenoid proportional valve 7, and a detailed description of their configuration will be omitted.

The first meter-out solenoid proportional valve 16 and the second meter-out solenoid proportional valve 17 place the meter-out spool 15 in the 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 moves the meter-out spool 15 to the first discharge position (see FIG. 5 ) by being energized while the second meter-out solenoid proportional valve 17 is in a non-energized state. 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 electric signal energized.
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.

<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. The placed meter-in spool 5 closes the first pump port P1, the second pump port P2, the first supply port S1, and the second supply port S2.

In addition, the first meter-out solenoid proportional valve 16 and the second meter-out solenoid proportional valve 17 are de-energized to place the meter-out spool 15 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).

As shown in FIG. 4, the meter-out spool 15 is moved in the direction of the arrow A1 to be placed in 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) and placed in the second discharge position. By placing the meter-out spool 15 in the second discharge position, the first tank port T1 and the first discharge port D1 are connected by the first meter-out flow path 21. As a result, the first tank port T1 is connected to 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 blocked by the meter-out spool 15.

The meter-in spool 5 is moved in the direction of the arrow B1 to the first supply position. In this case, the first meter-in electromagnetic proportional valve 6 is switched to an energized state while the second meter-in electromagnetic proportional valve 7 is in a non-energized state, so that the meter-in spool 5 is moved toward the second meter-in electromagnetic proportional valve 7 (see FIG. 2) and placed in the first supply position. By placing the meter-in spool 5 in the first supply position, the first pump port P1 and the first supply port S1 are connected by the first meter-in flow path 11. Also, by placing the meter-in spool 5 in the first supply position, the second pump port P2 and the second supply port S2 are connected by the second meter-in flow path 12. As a result, the first pump port P1 is connected to 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 connected to the head port Hp via the second meter-in flow path 12 and the second supply port S2, etc.

Specifically, the first pump port P1 is connected to 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, and the second pump port P2 is connected to 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, etc.

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, hydraulic oil is returned from the first discharge port D1 to the tank 120.

Meanwhile, hydraulic oil discharged from the discharge port of the first pump 110A passes through the first pump port P1, the first meter-in flow path 11, the first supply port S1, and the head port Hp, and flows into the cylinder head side of the cylinder 114, as indicated by the arrow Vs1. Specifically, hydraulic oil discharged from the discharge port of the first pump 110A passes 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 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 Vs1.
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 the present 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.

That is, when the meter-in spool 5 is moved in the direction of arrow B1 (an example of one direction in the claims), hydraulic oil from both 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 passes through the two pump ports P1, P2, two meter-in passages 11, 12, the first head passage 33, etc., and merges, 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.

As shown in Fig. 5, the meter-out spool 15 is moved in the direction of the arrow A2 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 to be 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 with each other through 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.

The meter-in spool 5 is also moved in the direction of arrow B2 to 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, so that the meter-in spool 5 is moved toward the first meter-in solenoid proportional valve 6 (see FIG. 2) and placed in the second supply position. By placing the meter-in spool 5 in the second supply position, the first pump port P1 and the first supply port S1 are connected by the first meter-in flow path 11. As a result, the first pump port P1 is connected to 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.

Specifically, the first pump port P1 is connected to 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 134.

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 flow path 22, the second bypass port G2, etc., toward the second rod flow path 32 (an example of a regeneration flow path) 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 flow path 133, the first head flow path 33, the second head flow path 34, the second discharge port D2, the second meter-out flow path 22, the second bypass port G2, the bypass flow path 37, the third check valve 73, the first bypass port G1, the second rod flow path 32, the first rod flow path 31, and the rod side flow path 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.

On the other hand, 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 into the piston rod 115 side of the cylinder 114 as indicated by the arrow Vs3. Specifically, 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 into 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 the threshold value, such as when lowering the 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.

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 as shown by an arrow E2 so as to be pushed into the cylinder 114.

In this way, the independent metering valve 2 is equipped with a meter-in spool 5 and a meter-out spool 15. By controlling the drive of the meter-in spool 5 and the meter-out spool 15, the piston rod 115 can be moved in two directions, the directions of the arrows E1 and E2. 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.

In addition, the meter-in spool 5 is driven and controlled to a first supply position by the first meter-in electromagnetic proportional valve 6, and the meter-out spool 15 is driven and controlled to a second discharge position by the second meter-out electromagnetic proportional valve 17. As a result, the piston rod 115 of the hydraulic cylinder 113 can be moved 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 electromagnetic proportional valve 7, and the meter-out spool 15 is driven and controlled to the first discharge position by the first meter-out electromagnetic proportional valve 16. As a result, the piston rod 115 of the hydraulic cylinder 113 can be moved in the direction of the arrow E2 (the other direction).

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 form an independent metering valve 2. As a result, when adjusting the independent metering valve 2 (i.e., the hydraulic control device 1) 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 easier to adjust the actual machine and shortens the adjustment period.

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.

The meter-in spool 5 and 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 meter-out spool 15, making it possible to respond to markets where electrification is expected in the future and increasing versatility.

The hydraulic control device 1 of this embodiment is configured to have one meter-in spool 5 and one meter-out spool 15, so that the piston rod 115 of the hydraulic cylinder 113 can be switched in two directions. Therefore, one meter-in spool 5 and one meter-out spool 15 can be used to switch the piston rod 115 in two directions. Therefore, it is not necessary to have, for example, two meter-in spools and two meter-out spools to switch the piston rod 115 in two directions. This simplifies the circuit configuration of the independent metering valve 2 (i.e., the meter-in spool and the meter-out spool).

As shown in FIG. 1, the 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, shortening the adjustment period.

As described above, the construction machine 100 according to this embodiment includes a boom 104, two pumps 110A and 110B that discharge hydraulic oil, a hydraulic control device 1 having a meter-in valve 4 that controls the flow rate of the hydraulic oil discharged from the two pumps 110A and 110B, and a hydraulic cylinder 113 for driving the boom 104 by flowing hydraulic oil whose flow rate is controlled by the meter-in valve 4. The meter-in valve 4 includes a valve body 3 having a spool hole 10 and two pump ports P1 and P2 connected to the spool hole 10, and a spool 5 that is movably provided in the spool hole 10. The hydraulic control device 1 includes solenoid valves 6 and 7 that move the spool 5, and a control unit 25 that controls the solenoid valves 6 and 7. When the meter-in valve 4 moves the spool 5 in one direction, the hydraulic oil from the two pump ports P1 and P2 is merged and the hydraulic oil flows into the hydraulic cylinder 113. When the spool 5 is moved in the other direction, the meter-in valve 4 allows only one of the hydraulic oil ports P1 and P2 to flow. The spool 5 has a notch 5c and a land 5b that can block the flow path and adjust the flow rate.

According to this configuration, the hydraulic oil from the two pump ports P1, P2 can be joined together by unidirectional movement of the spool 5 to flow into the hydraulic cylinder 113. For example, the amount of hydraulic oil supplied to the hydraulic cylinder 113 can be easily adjusted in response to fluctuations in the load on the hydraulic cylinder 113.
In addition, by moving the spool 5 in the other direction, only one of the two pump ports P1 and P2 is allowed to flow hydraulic oil, thereby achieving the minimum necessary output, which contributes to energy saving. For example, the raising and lowering operation of the boom 104 can be made energy-saving.
In addition, the spool 5 has the notches 5c and lands 5b that can block the flow passage and adjust the flow rate, so that the flow passage can be blocked and the flow rate can be adjusted with a simple structure.
In addition, since the hydraulic control device 1 is equipped with solenoid valves 6, 7 that move the spool 5 and a control unit 25 that controls the solenoid valves 6, 7, the drive control of the spool 5 can be electrically adjusted, thereby simplifying the circuit configuration.

The control method of this embodiment includes an ascent process for raising the boom 104, and a descent process for lowering the boom 104. In the ascent process, the spool 5 is moved in one direction to allow the hydraulic oil from the two pump ports P1, P2 to flow together. In the descent process, the spool 5 is moved in the other direction to allow only one of the hydraulic oils from the two pump ports P1, P2 to flow.

According to this method, in the raising stroke, the spool 5 is moved in one direction to allow the hydraulic oil from the two pump ports P1, P2 to merge and flow, and in the raising operation of the boom 104, the movement of the spool 5 in one direction allows the hydraulic oil from the two pump ports P1, P2 to merge and flow. In addition, in the lowering stroke, the spool 5 is moved in the other direction to allow only one of the hydraulic oils from the two pump ports P1, P2 to flow, which results in the minimum necessary output in the lowering operation of the boom 104, contributing to energy conservation. Therefore, the raising and lowering operation of the boom 104 can be energy-efficient.

In the above embodiment, an example has been described in which the hydraulic oil from the two pump ports P1, P2 is joined and flows when the spool 5 is moved in one direction, and only one of the hydraulic oils from the two pump ports P1, P2 is allowed to flow when the spool 5 is moved in the other direction, but this is not limiting. For example, at least one of the hydraulic oils from the two pump ports P1, P2 may be allowed to flow when the spool 5 is moved in the other direction.
For example, the configuration may be such that it is possible to switch between a case where only one of the hydraulic oils from the two pump ports P1, P2 flows when the spool 5 is moved in the other direction, and a case where the hydraulic oils from the two pump ports P1, P2 are joined and flow when the spool 5 is moved in the other direction. With this configuration, it is possible to select whether to use two pumps 110A, 110B or one pump depending on the usage status of the hydraulic cylinder 113.

In the above embodiment, an example has been described in which the spool 5 is moved in one direction to use hydraulic oil from the two pumps 110A, 110B, but this is not limiting. For example, the spool 5 may be moved in one direction to use hydraulic oil from only one of the two pumps 110A, 110B. In this case, for example, the flow path on the second pump 110B side may be closed to use hydraulic oil from only the first pump 110A. Alternatively, the flow path from the first pump 110A may be branched and connected to the flow path on the second pump 110B side.

Second Embodiment
6 is an explanatory diagram of an example of the operation of the hydraulic system 209 when pushing the arm of the second embodiment.
7 is an explanatory diagram of an example of the operation of the hydraulic system 209 when pulling the arm of the second embodiment.
In the above-described first embodiment, an example of the operation of the hydraulic system when raising and lowering a 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 a hydraulic system when pushing and pulling an arm. In Figures 6 and 7, the same components as those in the first embodiment are denoted by the same reference numerals, and detailed description thereof will be omitted.

6, in the hydraulic system 209 of this embodiment, when the arm is pushed, hydraulic oil is discharged from the two pumps 110A, 110B via the two pump ports P1, P2. That is, when the meter-in spool 5 is moved in the direction of the arrow B1 (one direction), hydraulic oil from both of the two pumps 110A, 110B is caused to flow together from the meter-in valve 4 via the two pump ports P1, P2. The hydraulic oil discharged from the two pumps 110A, 110B is joined via the two pump ports P1, P2, the two meter-in passages 11, 12, the first head passage 33, etc., and is then caused to flow from the meter-in valve 4 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 as indicated by an arrow E1 so as to be pushed into the cylinder 114.
In the hydraulic system 209 of this embodiment, the two pumps 110A, 110B have different discharge flow rates.

7, in hydraulic system 209 of this embodiment, when the arm is pulled, hydraulic oil is discharged from the two pumps 110A, 110B via the two pump ports P1, P2. That is, when meter-in spool 5 is moved in the direction of arrow B2 (the other direction), hydraulic oil from both pumps 110A, 110B is caused to flow together from meter-in valve 4 via the two pump ports P1, P2. The hydraulic oil discharged from the two pumps 110A, 110B joins together via the two pump ports P1, P2, two meter-in passages 11, 12, first rod passage 31, etc., and flows from meter-in valve 4 to the cylinder head side of hydraulic cylinder 113.
As a result, the piston rod 115 of the hydraulic cylinder 113 is pushed out as indicated by an arrow E2 so as to protrude from the cylinder 114.

In FIG. 7, the arrow Vs4 indicates the flow of hydraulic oil discharged from the discharge port of the second pump 110B through the second supply passage 132, the second pump port P2, 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 rod passage 31, the rod side passage 134, and the head port Hp toward the cylinder head side of the cylinder 114.

According to this configuration, when the spool 5 is moved in one direction, the meter-in valve 4 merges the hydraulic oil from the two pump ports P1, P2 and causes the hydraulic oil to flow to the hydraulic cylinder 113. By moving the spool 5 in one direction, the meter-in valve 4 can merge the hydraulic oil from the two pump ports P1, P2 and cause the hydraulic oil to flow to the hydraulic cylinder 113.
In addition, when the spool 5 is moved in the other direction, the meter-in valve 4 merges the hydraulic oil from the two pump ports P1, P2 and allows the hydraulic oil to flow to the hydraulic cylinder 113.
In addition, since the two pumps 110A, 110B have different discharge flow rates, the discharge flow rates of the two pumps 110A, 110B can be adjusted according to the usage status of the hydraulic cylinder 113. For example, energy can be saved by adjusting the discharge flow rates of the two pumps 110A, 110B according to the driving status of the arm.

Third Embodiment
FIG. 8 is an explanatory diagram of an example of the operation of the hydraulic system 309 when the meter-in spool of the third embodiment is located in the neutral position.
9 is an explanatory diagram of an example of the operation of the hydraulic system 309 when raising the boom in the third embodiment.
10 is an explanatory diagram of an example of the operation of the hydraulic system 309 when lowering the boom in the third embodiment.
In the above-described first embodiment, an example has been described in which the construction machine is equipped with two spools 5, 15 including one spool 5 to which two pump ports P1, P2 are connected, but this is not limiting. For example, the construction machine may be equipped with only one spool 5 to which two pump ports P1, P2 are connected. In Figures 8 to 10, the same reference numerals are used to designate the same components as those in the above-described first embodiment, and detailed descriptions thereof will be omitted.

As shown in FIG. 8, by placing the meter-in spool 5 in the neutral position, the first pump port P1, the second pump port P2, the first supply port S1, and the second supply port S2 are blocked.

9, in hydraulic system 309 of this embodiment, when the boom is raised, hydraulic oil from the two pumps 110A, 110B flows from the meter-in valve 4 via the two pump ports P1, P2. That is, when the meter-in spool 5 is moved in the direction of arrow B1 (one direction), hydraulic oil from both pumps 110A, 110B flows together from the meter-in valve 4 via the two pump ports P1, P2. The hydraulic oil discharged from the two pumps 110A, 110B flows together via the two pump ports P1, P2 and two meter-in passages 11, 12, etc., and is then flowed 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.

9, the arrow Vs31 indicates the flow of hydraulic oil discharged from the discharge port of the first pump 110A through the first supply passage 131, the first pump port P1, the first meter-in passage 11, the first supply port S1, a part of the bridge passage 30, the head side passage 133, and the head port Hp toward the cylinder head side of the cylinder 114, and the arrow Vs32 indicates the flow of hydraulic oil discharged from the discharge port of the second pump 110B through the second supply passage 132, the second pump port P2, the second meter-in passage 12, the second supply port S2, a part of the bridge passage 30, the head side passage 133, and the head port Hp toward the cylinder head side of the cylinder 114. In this embodiment, a part of the second meter-in passage 12 is formed by a land 305b without a notch (for example, a land having a shorter axial length than the land 5b with the notch 5c), etc.

10 , in hydraulic system 309 of this embodiment, when the boom is lowered, hydraulic oil from only one pump 110A flows from meter-in valve 4 via one pump port P1. That is, when meter-in spool 5 is moved in the direction of arrow B2 (the other direction), hydraulic oil from only one of two pumps 110A, 110B (only first pump 110A) flows from meter-in valve 4 via only one of two pump ports P1, P2 (only first pump port P1). Hydraulic oil discharged from first pump 110A flows from meter-in valve 4 to the piston rod 115 side of hydraulic cylinder 113 via first pump port P1, first meter-in flow path 11, etc.
As a result, the piston rod 115 of the hydraulic cylinder 113 is retracted as shown by an arrow E2 so as to be pushed into the cylinder 114.

In FIG. 10, the arrow Vs33 indicates the flow of hydraulic oil discharged from the discharge port of the first pump 110A through the first supply passage 131, the first pump port P1, the first meter-in passage 11, the first supply port S1, a part of the bridge passage 30, the rod-side passage 134, and the rod port Rp toward the piston rod 115 side of the cylinder 114.

According to this configuration, when the spool 5 is moved in one direction, the meter-in valve 4 allows the hydraulic oil from the two pump ports P1, P2 to join and flow, so that the movement of the spool 5 in one direction can cause the hydraulic oil from the two pump ports P1, P2 to join and flow.
In addition, when the spool 5 is moved in the other direction, the meter-in valve 4 allows only one of the two pump ports P1, P2 to flow hydraulic oil, thereby achieving the minimum required output, thereby contributing to energy saving. For example, the raising and lowering operation of the boom can be made energy-saving.

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.

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

In the above-described embodiment, an example was given in which the fluid system is a hydraulic system equipped with a hydraulic control device, but this is not limited thereto. 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.

In the above-described embodiment, an example has been described in which the fluid system includes two pumps, a fluid control device, and an actuator, but this is not limiting. For example, the fluid system may include three or more pumps. For example, the fluid system may not include a pump, but may include a fluid control device and an actuator. For example, the fluid system may not include an actuator, but may include at least two pumps and a fluid control device.

In the above-described embodiment, an example was given in which one spool is a meter-in spool that controls the amount of fluid supplied to the actuator, but this is not limited thereto. For example, the one spool may be a spool other than a meter-in spool.

In the above embodiment, the hydraulic cylinder 113 is used as an actuator, but this is not limiting. For example, the present invention may be applied to an actuator such as a hydraulic motor.

In the above-described embodiment, the solenoid valves are the proportional solenoid valves 6, 7, 16, and 17, but 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 electrical signal.

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. In addition, the above-described variations may be combined.

1...Hydraulic control device (fluid control device)
2...Independent metering valve (fluid valve)
3... Valve body 4... Meter-in valve (fluid valve)
5...Meter-in spool (one spool)
5b, 305b...land 5c...notch 6...first meter-in solenoid proportional valve (solenoid valve)
7...Second meter-in solenoid proportional valve (solenoid valve)
10...First spool hole (spool hole)
11...First meter-in passage (passage)
12...Second meter-in passage (passage)
15...Meter-out spool (spool)
25: Control unit 100: Hydraulic excavator (construction machine)
104... Boom 105... Arm 109, 209, 309... Hydraulic system (fluid system)
110...Hydraulic pump (pump)
110A...First pump (pump)
110B...Second pump (pump)
113...Hydraulic cylinder (actuator)
B1: One direction B2: Other direction P1: First pump port (flow path)
P2: Second pump port (flow path)

Claims (3)

at least two pumps for discharging fluid;
A fluid control device having a fluid valve that controls the flow rate of the fluid discharged from the two pumps and flows the fluid to an actuator,
The fluid valve includes:
a valve body having a first spool hole and a second spool hole , and two flow passages connected to the first spool hole ;
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,
A fluid system in which, when the meter-in spool is moved in one direction, the fluids from the two flow paths are joined together to cause the fluid to flow to the actuator. Boom and
Two pumps for discharging fluid;
a fluid control device having a fluid valve for controlling the flow rate of the fluid discharged from the two pumps;
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 hole and a second spool hole , and two flow passages connected to the first spool hole ;
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-in spool is moved in one direction, the fluids from the two flow paths are joined together to flow to the actuator,
When the meter-in spool is moved in the other direction, only one of the fluids from the two flow paths flows. An arm,
Two pumps for discharging fluid;
a fluid control device having a fluid valve for controlling the flow rate of the fluid discharged from the two pumps;
an actuator for driving the arm by flowing a fluid whose flow rate is controlled by the fluid valve,
The fluid valve includes:
a valve body having a first spool hole and a second spool hole , and two flow passages connected to the first spool hole ;
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,
The discharge flow rates of the two pumps are different,
When the meter-in spool is moved in one direction, the fluids from the two flow paths are joined together to flow to the actuator,
When the meter-in spool is moved in the other direction, the fluids from the two flow paths are joined together and supplied to the actuator.

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