Working machine

Abstract

The working machine comprises: a machine body (2), a first hydraulic actuator (C3, AC1) mounted on the machine body, a first control valve (V2, AV) for controlling the first hydraulic actuator, a control device (U1) for controlling the first control valve, and a second hydraulic actuator (AC, M1) different from the first hydraulic actuator. When the second hydraulic actuator and the first hydraulic actuator are operated in combination, the control device (U1) reduces the amount of change (53, 62, 153) in the flow rate of working oil supplied from the first control valve to the first hydraulic actuator relative to the change in the operation amount of the first hydraulic actuator, compared to when the first hydraulic actuator is operated alone.

Description

Technical Field

[0001] The present invention relates to working machines such as backhoe excavators. Background Art

[0002] Conventionally, a working machine disclosed in Patent Document 1 is known.

[0003] The working machine disclosed in Patent Document 1 has a boom supported by a machine body so as to be able to swing up and down. The boom is driven by a boom cylinder.

[0004] The working machine disclosed in Patent Document 1 includes a travel device that supports a machine body so that the machine body can travel. The travel device is driven by a travel motor that is composed of a hydraulic motor.

[0005] Prior art literature

[0006] Patent Literature

[0007] Patent Document 1: Japanese Patent Publication No. 2009-79366 Summary of the invention

[0008] Problems to be solved by the invention

[0009] However, for example, when a boom cylinder and another hydraulic actuator different from the boom cylinder are operated in combination, the boom and the components driven by the other hydraulic actuator may not operate in coordination.

[0010] Furthermore, when a hydraulic actuator other than the travel motor is operated during travel, the flow rate of hydraulic oil supplied to the travel motor is sucked away by the hydraulic actuator, thereby reducing the travel speed and causing a problem of seizure.

[0011] The present invention has been made in view of the above-mentioned problems, and an object of the present invention is to provide a working machine capable of coordinating the operations of a component operated by a first hydraulic actuator and a component operated by a second hydraulic actuator.

[0012] Another object of the present invention is to provide a working machine capable of suppressing a decrease in traveling speed when a hydraulic actuator other than a traveling motor is operated during traveling.

[0013] Technical solutions to solve problems

[0014] A working machine involved in one embodiment of the present invention comprises: a machine body; a first hydraulic actuator mounted on the machine body; a first control valve that controls the first hydraulic actuator; a control device that controls the first control valve; and a second hydraulic actuator different from the first hydraulic actuator, wherein when the second hydraulic actuator and the first hydraulic actuator are operated in combination, the control device reduces the change in the flow rate of working oil supplied from the first control valve to the first hydraulic actuator relative to the change in the operation amount of the first hydraulic actuator, compared to when the first hydraulic actuator is operated alone.

[0015] In addition, it is provided with a boom which is supported on the machine body so as to be able to swing up and down, the first hydraulic actuator is a boom cylinder which swings the boom up and down, the first control valve is a boom control valve which controls the boom cylinder, and the second hydraulic actuator is another hydraulic actuator different from the boom cylinder.

[0016] Furthermore, the control device includes a boom flow rate suppressing unit for reducing the amount of change by reducing a flow rate of hydraulic oil supplied from the boom control valve to the boom cylinder when the boom cylinder is operated while the other hydraulic actuator is being operated.

[0017] Furthermore, the boom control valve is pilot operated by a pilot control pressure controlled by a control signal transmitted from the control device, and when the boom cylinder is operated while the other hydraulic actuators are being operated, the boom flow rate suppressing unit reduces the pilot control pressure.

[0018] Furthermore, the boom control valve is controlled based on a current value supplied from the control device, and when the boom cylinder is operated while the other hydraulic actuator is being operated, the boom flow rate suppressing unit reduces a current value supplied to the boom control valve.

[0019] In addition, it is provided with: a boom connected to the front end side of the boom in a manner that allows it to swing in a direction approaching the boom, i.e., a boom loading direction, and in a direction away from the boom, i.e., a boom unloading direction; and a boom cylinder that swings the boom, and the other hydraulic actuator is the boom cylinder. When the boom cylinder is operated while the boom cylinder is operated, the boom flow suppression unit reduces the flow of the working oil supplied from the boom control valve to the boom cylinder.

[0020] In addition, when the boom is raised while the boom is swung in the boom loading direction, or when the boom is lowered while the boom is swung in the boom unloading direction, the boom flow suppression unit reduces the flow of the working oil supplied from the boom control valve to the boom cylinder.

[0021] In addition, there is an operating component for operating the boom cylinder, and the control device has a control unit. When the boom cylinder is operated alone, the control unit controls the flow rate of the working oil supplied from the boom control valve to the boom cylinder according to the operation amount of the operating component. Relative to the operation amount of the operating component, the boom flow suppression unit supplies working oil from the boom control valve to the boom cylinder at a flow rate less than the flow rate of the working oil controlled by the control unit according to the operation amount.

[0022] In addition, the control device has a boom flow increment unit, which sets the setting of the starting side of the boom control valve of the working oil flow relative to the operation amount of the boom cylinder to be higher when the other hydraulic actuators and the boom cylinder are subjected to a combined operation, compared with when the boom cylinder is operated alone, and the more the operation amount of the boom cylinder is increased, the smaller the difference in the working oil flow relative to the operation amount of the boom cylinder when the combined operation is performed and when the single operation is performed, thereby reducing the change amount.

[0023] Furthermore, the boom control valve is pilot operated based on a pilot pressure controlled by a control signal transmitted from the control device, and when the other hydraulic actuator and the boom cylinder are compositely operated, the boom flow rate increasing section increases the pilot pressure.

[0024] Furthermore, the boom control valve is controlled based on a current value supplied from the control device, and when the other hydraulic actuator and the boom cylinder are operated in combination, the boom flow rate increasing unit increases a current value supplied to the boom control valve.

[0025] In addition, it is provided with: a boom connected to the front end side of the boom in a manner that allows it to swing in a direction approaching the boom, i.e., a boom loading direction, and in a direction away from the boom, i.e., a boom unloading direction; and a boom cylinder that swings the boom, and the other hydraulic actuator is the boom cylinder. When the boom cylinder is operated while the boom cylinder is operated, the boom flow increment unit increases the flow of the working oil supplied from the boom control valve to the boom cylinder.

[0026] In addition, when the boom is raised while the boom is swung in the boom loading direction, or when the boom is lowered while the boom is swung in the boom unloading direction, the boom flow increasing unit increases the flow rate of the working oil supplied from the boom control valve to the boom cylinder.

[0027] In addition, there is an operating component for operating the boom cylinder, and the control device has a control unit. When the boom cylinder is operated alone, the control unit controls the flow rate of the working oil supplied from the boom control valve to the boom cylinder according to the operation amount of the operating component. Relative to the operation amount of the operating component, the boom flow increment unit supplies working oil from the boom control valve to the boom cylinder at a flow rate greater than the flow rate of the working oil controlled by the control unit according to the operation amount.

[0028] Furthermore, when the other hydraulic actuator is operated while the boom cylinder is being independently operated in the direction of raising the boom, the control device deactivates the boom flow rate increasing section.

[0029] In addition, there is a travel device that supports the body in a travelable manner, the second hydraulic actuator is a travel motor composed of a hydraulic motor that drives the travel device, the first hydraulic actuator is another hydraulic actuator different from the travel motor, the first control valve is an actuator control valve that controls the other hydraulic actuator, and the control device has an actuator flow suppression unit. When the other hydraulic actuator is operated while the travel motor is being driven, the actuator flow suppression unit reduces the flow rate of the working oil supplied from the actuator control valve to the other hydraulic actuator.

[0030] Furthermore, the actuator control valve is pilot operated by a pilot control pressure controlled by a control signal transmitted from the control device, and when the other hydraulic actuator is operated while the travel device is being driven, the actuator flow rate suppressing unit reduces the pilot control pressure.

[0031] Furthermore, the actuator control valve is controlled according to a current value supplied from the control device, and when the other hydraulic actuator is operated while the travel device is being driven, the actuator flow rate suppressing unit reduces a current value supplied to the actuator control valve.

[0032] In addition, there is an operating component for operating the other hydraulic actuator, and the control device has a control unit. When the other hydraulic actuator is operated alone, the control unit controls the flow rate of the working oil supplied from the actuator control valve to the other hydraulic actuator according to the operation amount of the operating component. Relative to the operation amount of the operating component, the actuator flow suppression unit supplies working oil from the actuator control valve to the other hydraulic actuator at a flow rate less than the flow rate of the working oil controlled by the control unit according to the operation amount.

[0033] In addition, it is provided with: a boom cylinder, which drives a boom supported on the body in a manner that can swing up and down; a dipper arm cylinder, which drives a dipper arm connected to the front end side of the boom in a manner that can swing; a work tool cylinder, which drives a work tool connected to the front end side of the dipper arm; and a rotary motor, which is a hydraulic motor that rotates the body around an axis extending in the up and down direction, and the other hydraulic actuator includes at least the boom cylinder, the dipper arm cylinder, the work tool cylinder and the rotary motor.

[0034] In addition, it is provided with: a variable capacity pump which discharges working oil for operating multiple hydraulic actuators including the first hydraulic actuator and the second hydraulic actuator; and a load sensing system which controls the pump so that the pressure difference obtained by subtracting the highest load pressure among the multiple hydraulic actuators from the discharge pressure of the pump becomes a constant pressure.

[0035] In addition, the working machine involved in other embodiments comprises: a body; a travel device that supports the body in a travelable manner; a travel motor that is composed of a hydraulic motor that drives the travel device; another hydraulic actuator different from the travel motor; an actuator control valve that controls the other hydraulic actuator; and a control device that controls the actuator control valve, the control device having an actuator flow suppression unit that reduces the flow of working oil supplied from the actuator control valve to the other hydraulic actuator when the other hydraulic actuator is operated while the travel device is being driven.

[0036] Furthermore, the actuator control valve is pilot operated by a pilot control pressure controlled by a control signal transmitted from the control device, and when the other hydraulic actuator is operated while the travel device is being driven, the actuator flow rate suppressing unit reduces the pilot control pressure.

[0037] Furthermore, the actuator control valve is controlled according to a current value supplied from the control device, and when the other hydraulic actuator is operated while the travel device is being driven, the actuator flow rate suppressing unit reduces a current value supplied to the actuator control valve.

[0038] In addition, there is an operating component for operating the other hydraulic actuator, and the control device has a control unit. When the other hydraulic actuator is operated alone, the control unit controls the flow rate of the working oil supplied from the actuator control valve to the other hydraulic actuator according to the operation amount of the operating component. Relative to the operation amount of the operating component, the actuator flow suppression unit supplies working oil from the actuator control valve to the other hydraulic actuator at a flow rate less than the flow rate of the working oil controlled by the control unit according to the operation amount.

[0039] In addition, it is provided with: a boom cylinder, which drives a boom supported on the body in a manner that can swing up and down; a dipper arm cylinder, which drives a dipper arm connected to the front end side of the boom in a manner that can swing; a work tool cylinder, which drives a work tool connected to the front end side of the dipper arm; and a rotary motor, which is a hydraulic motor that rotates the body around an axis extending in the up and down direction, and the other hydraulic actuator includes at least the boom cylinder, the dipper arm cylinder, the work tool cylinder and the rotary motor.

[0040] In addition, it is provided with: a variable capacity pump which discharges working oil for operating multiple hydraulic actuators including the travel motor and the other hydraulic actuator; and a load sensing system which controls the pump so that the pressure difference obtained by subtracting the highest load pressure among the multiple hydraulic actuators from the discharge pressure of the pump becomes a constant pressure.

[0041] Effects of the Invention

[0042] According to the above working machine, when the first hydraulic actuator and the second hydraulic actuator are operated in combination, the operations of the component operated by the first hydraulic actuator and the component operated by the second hydraulic actuator can be coordinated.

[0043] In addition, according to the above-mentioned working machine, when another hydraulic actuator different from the travel motor is operated during driving, the flow rate of the working oil supplied from the actuator control valve to the other hydraulic actuator can be reduced, thereby ensuring the flow rate of the working oil supplied to the travel motor and suppressing the reduction in travel speed. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] Figure 1 It is a side view of the working machine.

[0045] Figure 2 This is a top view of the working machine.

[0046] Figure 3 It is a schematic diagram of the hydraulic system.

[0047] Figure 4 A circuit diagram of a part of a hydraulic system.

[0048] Figure 5 This is a circuit diagram of a part of a control valve.

[0049] Figure 6 This is a circuit diagram of the other parts of the control valve.

[0050] Figure 7 It is the circuit diagram of another part of the control valve.

[0051] Figure 8This is a schematic diagram of the control system according to the first embodiment.

[0052] Fig. 9 This is a diagram showing the relationship between the operation amount of the operating member and the flow rate of the hydraulic oil according to the first embodiment.

[0053] Fig.10 This is a structural diagram showing another form of a control valve, etc.

[0054] Fig.11 This is a structural diagram showing another embodiment of a control valve and the like.

[0055] Fig.12 This is a schematic diagram of a control system according to the second embodiment.

[0056] Fig.13 This is a diagram showing the relationship between the operation amount of the operating member and the flow rate of the hydraulic oil according to the second embodiment.

[0057] Fig.14 This is a schematic diagram of a control system according to the third embodiment.

[0058] Fig.15 This is a diagram showing the relationship between the operation amount of the operating member and the flow rate of the hydraulic oil according to the third embodiment. DETAILED DESCRIPTION

[0059] Hereinafter, one embodiment of the present invention will be described with reference to the drawings as appropriate.

[0060] Figure 1 It is a schematic side view showing the overall structure of the working machine 1 according to the present embodiment. Figure 2 It is a schematic plan view of the working machine 1. In the present embodiment, a backhoe which is a swing working machine is exemplified as the working machine 1.

[0061] like Figure 1 , Figure 2 As shown, the working machine 1 includes a machine body (turntable) 2, a travel device 3, and a working device 4. A cab 5 is mounted on the machine body 2. A driver's seat 6 is provided in the cab 5 for an operator (driver) to sit.

[0062] In the present embodiment, the direction ( Figure 1 , Figure 2 The direction of arrow A1 is called the front (front of the machine body), and the direction toward the rear of the operator ( Figure 1 , Figure 2 The direction of arrow A2 is called the rear (the rear of the machine body). Figure 1 , Figure 2The direction of the arrow K1 is referred to as the front-rear direction (the front-rear direction of the machine body). Figure 1 The front side, Figure 2 The direction of arrow A3 is called the left direction, and the direction toward the right side of the operator ( Figure 1 The inside of Figure 2 The direction of arrow A4 is referred to as the right direction. In addition, the horizontal direction orthogonal to the front-rear direction (machine body front-rear direction) K1 is referred to as the machine body width direction K2 (refer to Figure 2 ).

[0063] like Figure 1 , Figure 2 As shown, the travel device 3 is a device that supports the machine body 2 in a travelable manner. The travel device 3 includes a travel frame 3A, a first travel device 3L provided on the left side of the travel frame 3A, and a second travel device 3R provided on the right side of the travel frame 3A. The first travel device 3L and the second travel device 3R are crawler-type travel devices. The travel device 3 is driven by a travel motor M1 composed of a hydraulic motor (hydraulic actuator). In detail, the first travel device 3L is driven by the first travel motor ML, and the second travel device 3R is driven by the second travel motor MR.

[0064] A bulldozer 7 is mounted on the front portion of the travel device 3. The bulldozer 7 is driven by a bulldozer cylinder C1. Specifically, the bulldozer cylinder C1 is composed of a hydraulic cylinder (hydraulic actuator), and the bulldozer blade 7A of the bulldozer 7 is raised and lowered by extending and retracting the bulldozer cylinder C1.

[0065] like Figure 1 As shown, the machine body 2 is supported by the travel device 3 (travel frame 3A) so as to be rotatable about a rotation axis X1 via a slewing bearing 8. The slewing axis X1 is an axis (vertical axis) extending in the vertical direction through the center of the slewing bearing 8.

[0066] like Figure 2 As shown, the cab 5 is mounted on one side (left side) in the width direction K2 of the machine body 2. The cab 5 is arranged on one side (left side) in the width direction K2 of the machine body 2 relative to a center line Y1 passing through the rotation axis X1 and extending in the front-rear direction K1.

[0067] like Figure 2 As shown, the prime mover E1 is mounted on the other side (right side) of the width direction K2 of the machine body 2. The prime mover E1 is mounted on the machine body 2 in a longitudinal manner. The longitudinal arrangement means that the axis of the crankshaft of the prime mover E1 is arranged to extend along the front-rear direction K1. The prime mover E1 is a diesel engine. In addition, the prime mover E1 can be a gasoline engine, an electric motor, or a hybrid type having an engine and an electric motor.

[0068] A pressure oil supply unit 18 is provided at the rear of the prime mover E1. The pressure oil supply unit 18 is driven by the power of the prime mover E1, and pressurizes and discharges the working oil used for the hydraulic drive unit. The hydraulic drive unit is, for example, a hydraulic actuator equipped on the working machine 1. A radiator R1, an oil cooler O1, and a condenser CD are arranged in front of the prime mover E1 and mounted on the machine body 2. The radiator R1 is a cooling device for cooling the cooling water (fluid) of the prime mover E1, and the oil cooler O1 is a cooling device for cooling the working oil (fluid). In addition, the condenser CD is a cooling device (condenser) that cools the refrigerant (fluid) of the air conditioning device (air conditioner) equipped on the working machine 1.

[0069] A cooling fan F1 is provided between the radiator R1 and the prime mover E1 to generate cooling air for cooling the prime mover E1. The cooling fan F1 is driven by the power of the prime mover E1 to generate cooling air that flows from the front to the rear.

[0070] like Figure 1 As shown, the machine body 2 has a base plate (hereinafter referred to as a rotating base plate) 9 that rotates around a rotation axis X1. The rotating base plate 9 is formed of a steel plate or the like, and constitutes the bottom of the machine body 2. On the upper surface of the rotating base plate 9, longitudinal ribs 9A as reinforcing components are provided from the front to the rear. In addition, in addition to the longitudinal ribs 9A, the rotating base plate 9 is also provided with components for supporting objects such as equipment mounted on the machine body 2, thereby constituting a rotating frame as the skeleton of the machine body 2. The horizontal periphery of the rotating frame is covered by a rotating cover.

[0071] A counterweight 10 is provided at the rear of the machine body 2. The counterweight 10 is arranged at the rear of the machine body 2 and the lower part thereof is mounted on the rotating base plate 9.

[0072] like Figure 2 As shown, a fuel tank T1 and a hydraulic oil tank T2 are mounted on the rear part of the machine body 2 and arranged side by side in the machine body width direction K2. The fuel tank T1 is a tank for storing fuel for the prime mover E1. The hydraulic oil tank T2 is a tank for storing hydraulic oil.

[0073] like Figure 2As shown, a rotary motor MT is arranged at the front of the rotary base plate 9 (machine body 2) and in the center of the machine body width direction K2. The rotary base plate 9 is driven to rotate around the rotary axis X1 by the rotary motor MT. The rotary motor MT is a hydraulic motor (hydraulic actuator). A rotary joint S1 is arranged at the position of the rotary axis X1. The rotary joint S1 is a hydraulic device for circulating the working oil, and is a rotary joint (rotary joint) for circulating the working oil between the hydraulic device on the machine body 2 side and the hydraulic device on the travel device 3 side. A control valve (hydraulic device) CV is arranged behind the rotary joint S1. The control valve CV is a composite control valve (hydraulic device) of a spliced ​​type having a plurality of control valves stacked and combined in the up and down directions. A control device U1 is arranged below the cab 5.

[0074] An operating device 1B for operating the working machine 1 is provided in the cab 5. The operating device 1B is provided in front of the operator's seat 6. The operator's seat 6 and the operating device 1B constitute a driving section 1C.

[0075] like Figure 2 As shown, the machine body 2 has a support bracket 13 at the front part slightly to the right of the center in the machine body width direction K2. The support bracket 13 is fixed to the front part of the longitudinal rib 9A and is provided to protrude forward from the machine body 2.

[0076] like Figure 1 , Figure 2 As shown, the front portion of the support bracket 13 (the portion protruding from the machine body 2) is mounted via a swing shaft 14A in a manner that allows the swing bracket 14 to swing around an axis extending in the vertical direction, that is, a swing axis X2. Therefore, the swing bracket 14 can rotate in the machine body width direction K2 (in the horizontal direction with the swing shaft 14A as the center).

[0077] like Figure 1 As shown, the working device 4 is supported by a swing bracket 14 (machine body 2).

[0078] The working device 4 includes: a boom 15 supported by the machine body 2 so as to be able to swing up and down (swing in the up and down directions); a dipper arm 16 pivotally supported and connected to the boom 15 so as to be able to swing; and a working tool (bucket) 17 pivotally supported and connected to the dipper arm 16 so as to be able to swing.

[0079] The base of the boom 15 is pivotally supported by a pivot shaft on the upper portion of the swing bracket 14. Specifically, the base of the boom 15 is pivotally mounted on the upper portion of the swing bracket 14 so as to be rotatable about a horizontal axis (an axis extending in the width direction K2 of the machine body) when the boom 15 is facing the front direction of the machine body. Thus, the boom 15 can swing in the up-and-down direction.

[0080] The boom 16 is pivotally supported on the front end side of the boom 15 via a pivot. Specifically, the boom 16 is pivotally mounted on the boom 15 so as to be rotatable about a horizontal axis when the boom 15 is facing the front direction of the machine body. Thus, the boom 16 can swing in the front-rear direction K1 or in the up-down direction. In addition, the boom 16 can swing in the direction approaching the boom 15, i.e., the boom loading direction D1, and in the direction away from the boom 15, i.e., the boom unloading direction D2.

[0081] The working tool 17 is pivotally supported on the front end side of the boom 16 via a pivot. In detail, the working tool 17 is pivotally mounted on the boom 16 so as to be rotatable around a horizontal axis when the boom 15 is facing the front direction of the machine body. As a result, the working tool 17 can be swung in a direction approaching the boom 16 (bucket loading direction) and in a direction away from the boom 16 (bucket unloading direction). In addition, the bucket serving as the working tool 17 is provided on the boom 16 in a manner capable of performing a digging action and a dumping action. The digging action refers to an action of swinging the working tool 17 in a direction approaching the boom 15, for example, an action in the case of digging up earth and sand. In addition, the dumping action refers to an action of swinging the working tool 17 in a direction away from the boom 15, for example, an action in the case of causing the dug earth and sand to fall (discharge).

[0082] In addition, as the working tool 17, working tools (attachments) such as pallet forks, branch forks, grabs, hydraulic crushers, angle brooms, ground-breaking augers, snow blowers, sweepers, lawn mowers, hydraulic breakers, etc. with hydraulic actuators (hydraulic attachments) can be installed instead of the bucket.

[0083] The swing bracket 14 can be swung by extending and retracting the swing cylinder C2 provided in the machine body 2. The boom 15 can be swung up and down by extending and retracting the boom cylinder C3. The dipper arm 16 can be swung in the dipper arm shoveling direction D1 and the dipper arm unloading direction D2 by extending and retracting the dipper arm cylinder C4. The working tool 17 can be swung in the bucket shoveling direction and the bucket unloading direction by extending and retracting the working tool cylinder (bucket cylinder) C5. The swing cylinder C2, the boom cylinder C3, the dipper arm cylinder C4, and the working tool cylinder C5 are composed of hydraulic cylinders (hydraulic actuators).

[0084] Next, refer to Figure 3 to Figure 7 A hydraulic system for operating various hydraulic actuators ML, MR, MT, and C1 to C6 provided in the working machine 1 will be described.

[0085] like Figure 3 As shown, the hydraulic system includes a control valve CV, a pressure oil supply unit 18, and a flow control unit 19. The control valve CV is configured by arranging control valves V1 to V10 for controlling various hydraulic actuators ML, MR, MT, and C1 to C6, an inlet block B2 for taking in pressure oil, and a pair of outlet blocks B1 and B3 for discharging pressure oil in one direction.

[0086] like Figure 3 As shown, in the present embodiment, the control valve CV is sequentially configured with a first outlet block B1, a work tool control valve V1 for controlling a work tool cylinder C5, a boom control valve V2 for controlling a boom cylinder C3, a first bulldozer control valve V3 for controlling a bulldozer cylinder C1, a second travel control valve V4 for controlling a travel motor MR of a second travel device 3R, an inlet block B2, a first travel control valve V5 for controlling a travel motor ML of a first travel device 3L, a second bulldozer control valve V6 for controlling a bulldozer cylinder C1, an arm control valve V7 for controlling an arm cylinder C4, a swing control valve V8 for controlling a swing motor MT, a swing control valve V9 for controlling a swing cylinder C2, an SP control valve V10 for controlling an attachment actuator (hydraulic actuator) C6 equipped with the hydraulic attachment when a hydraulic attachment is mounted as a work tool 17, and a second outlet block B3 (in Figure 3 and connecting them to each other.

[0087] like Figures 4 to 7 As shown, each control valve V1 to V10 is constructed by assembling a directional switching valve DV1 to DV10 and a pressure compensating valve (compensating valve) V11 in a valve body. The directional switching valves DV1 to DV10 are valves that switch the direction of the working oil relative to the hydraulic actuators ML, MR, MT, C1 to C6 that are the objects of control. The pressure compensating valve V11 is provided on the downstream side of the pressure oil supply relative to the directional switching valves DV1 to DV10 and on the upstream side of the pressure oil supply relative to the hydraulic actuators ML, MR, MT, C1 to C6 that are the objects of control. When a plurality of the control valves V1 to V10 are used, the pressure compensating valve V11 functions as a load adjustment between the hydraulic actuators ML, MR, MT, C1 to C6.

[0088] A first relief valve V12 and a first unloading valve V13 are assembled in the first outlet block B1, and a travel independent valve V14 is assembled in the inlet block B2. The first relief valve V12 is a main relief valve that regulates the pressure of hydraulic oil discharged from a first pressure oil discharge port P1 described later.

[0089] The travel independent valve V14 is constituted by a direct acting spool type switching valve and is constituted by a pilot operated switching valve which is switched by a pilot pressure.

[0090] A second relief valve V15 and a second unloading valve V16 are incorporated in the second outlet block B3. The second relief valve V15 is a main relief valve that regulates the pressure of the hydraulic oil discharged from a second pressure oil discharge port P2 described later.

[0091] Each directional switching valve DV1~DV10 is composed of a direct-acting slide valve type switching valve. In addition, each directional switching valve DV1~DV10 is a control valve electrically controlled by the control device U1. In detail, each directional switching valve DV1~DV10 adopts, for example, a pilot-operated proportional solenoid valve. The pilot-operated proportional solenoid valve is a valve that controls the direction and flow rate of the flow of the working oil by moving the slide valve by a pilot control pressure controlled by a proportional solenoid. In detail, the pilot-operated proportional solenoid valve is a two-stage direction and flow control valve that uses a proportional solenoid pressure reducing valve with two proportional solenoids in the pilot part. The flow rate is controlled by changing the input current to the proportional solenoid, and the direction is controlled by applying a current to one of the two proportional solenoids.

[0092] like Figure 4 As shown, the hydraulic pump as the pressure oil supply source of the hydraulic system is equipped with a first pump 21 for supplying working oil to operate the hydraulic actuators ML, MR, MT, C1 to C6, and a second pump 22 for supplying signal pressure oil such as pilot control pressure and detection signal. These first pump 21 and second pump 22 are provided in the pressure oil supply unit 18 and driven by the prime mover E1.

[0093] The first pump 21 is a variable capacity pump, and in this embodiment, is composed of a swash plate type variable capacity axial pump having the function of an equal flow double pump that discharges an equal amount of working oil from two independent pressure oil discharge ports P1 and P2. In detail, the first pump 21 adopts a split flow hydraulic pump having a mechanism for alternately discharging working oil from a piston / cylinder set to discharge grooves formed inside and outside the valve plate.

[0094] One of the pressure oil discharge ports from the first pump 21 is referred to as a first pressure oil discharge port P1 , and the other pressure oil discharge port is referred to as a second pressure oil discharge port P2 .

[0095] Furthermore, in the present embodiment, the pressure oil discharge outlets discharged from the hydraulic pump having two pump functions are set as the first and second pressure oil discharge outlets P1 and P2, but the pressure oil discharge outlet of one of the two independently formed hydraulic pumps may be set as the first pressure oil discharge outlet, and the pressure oil discharge outlet of the other hydraulic pump may be set as the second pressure oil discharge outlet.

[0096] The pressure oil supply unit 18 is provided with a pressing piston 23 for pressing the swash plate of the first pump 21 and a flow rate compensation piston 24 for controlling the swash plate of the first pump 21 .

[0097] The first pump 21 is configured to utilize its own pressure to press the inclined plate in the direction of increasing the pump flow via the pressing piston 23, and is configured to utilize the flow compensation piston 24 to cause a force that counteracts the pressing force of the pressing piston 23 to act on the inclined plate, and the discharge flow of the first pump 21 is controlled by controlling the pressure acting on the flow compensation piston 24.

[0098] Therefore, when the pressure acting on the flow rate compensation piston 24 disappears, the swash plate angle of the first pump 21 becomes MAX, and the maximum flow rate is discharged.

[0099] like Figure 4 As shown, the flow control unit 19 performs swash plate control of the first pump 21 by controlling the pressure acting on the flow compensation piston 24 through a flow compensation valve V17 provided in the flow control unit 19 .

[0100] In addition, the pressure oil supply unit 18 is provided with a spring 25 and a slide valve 26 for controlling the pump horsepower (torque) of the first pump 21, which is configured to limit the horsepower (torque) absorbed by the first pump 21 from the prime mover E1 when the discharge pressure of the first pump 21 reaches a preset pressure.

[0101] The second pump 22 is constituted by a fixed displacement gear pump, and the discharge oil of the second pump 22 is discharged from a third pressure oil discharge port P3.

[0102] The first pressure oil discharge port P1 is connected to the inlet block B2 via the first discharge path a, and the second pressure oil discharge port P2 is connected to the inlet block B2 via the second discharge path b.

[0103] The first exhaust path a is connected to the first pressure oil supply path d, and the first pressure oil supply path d is formed from the inlet block B2 via the valve body of the second travel control valve V4 → the valve body of the first control valve V3 for bulldozers → the valve body of the boom control valve V2 → the valve body of the working tool control valve V1 to reach the first outlet block B1, and branches at the first outlet block B1 (on the end side of the flow path) to be connected to the first overflow valve V12 and the first unloading valve V13.

[0104] Working oil can be supplied from the first pressure oil supply path d via the pressure oil branch path f to the second travel control valve V4, the first bulldozing control valve V3, the boom control valve V2, and the direction switching valves DV4, DV3, DV2, and DV1 of the working tool control valve V1.

[0105] The first relief valve V12 and the first unloading valve V13 are connected to the drain oil passage g. The drain oil passage g is formed from the first outlet block B1 via the valve body of the working tool control valve V1 → the valve body of the boom control valve V2 → the valve body of the first control valve V3 for bulldozing → the valve body of the second travel control valve V4 → the inlet block B2 → the valve body of the first travel control valve V5 → the valve body of the second control valve V6 for bulldozing → the valve body of the arm control valve V7 → the valve body of the swing control valve V8 → the valve body of the swing control valve V9 → the valve body of the SP control valve V10 to the second outlet block B3. The hydraulic oil flowing in the drain oil passage g is discharged from the second outlet block B3 to the hydraulic oil tank T2.

[0106] The second discharge path b is connected to the second pressure oil supply path e. The second pressure oil supply path e is formed from the inlet block B2 via the valve body of the first travel control valve V5 → the valve body of the second dozer control valve V6 → the valve body of the boom control valve V7 → the valve body of the swing control valve V8 → the valve body of the swing control valve V9 → the valve body of the SP control valve V10 to the second outlet block B3, and branches at the second outlet block B3 (on the flow path end side) to be connected to the second relief valve V15 and the second unloading valve V16.

[0107] Working oil can be supplied from the second pressure oil supply path e via the pressure oil branch path h to the first travel control valve V5, the second control valve V6 for bulldozing, the boom control valve V7, the swing control valve V8, the swing control valve V9, and the SP control valve V10 to the directional switching valves DV5, DV6, DV7, DV8, DV9, and DV10.

[0108] The hydraulic oil supplied to each control valve V1 to V10 is supplied to and discharged from each hydraulic actuator ML, MR, MT, C1 to C6. That is, the hydraulic system includes a hydraulic circuit that supplies and discharges the hydraulic oil to and from each hydraulic actuator ML, MR, MT, C1 to C6.

[0109] The second relief valve V15 and the second unloading valve V16 are connected to the discharge oil passage g.

[0110] The first pressure oil supply passage d and the second pressure oil supply passage e are connected to each other via a communication passage j that crosses the travel independent valve V14 in the inlet block B2.

[0111] The travel independent valve V14 is switchable between an independent position 27 for blocking the flow of the pressure oil in the communication passage j and a merging position 28 for allowing the flow of the pressure oil in the communication passage j.

[0112] When the travel independent valve V14 is switched to the independent position 27, the working oil from the first pressure oil discharge outlet P1 can be supplied to the second travel control valve V4 and the respective direction switching valves DV4 and DV3 of the first control valve V3 for bulldozers, and the working oil from the second pressure oil discharge outlet P2 can be supplied to the respective direction switching valves DV5 and DV6 of the first travel control valve V5 and the second control valve V6 for bulldozers. The working oil from the first pressure oil discharge outlet P1 will not be supplied to the first travel control valve V5 and the second control valve V6 for bulldozers. In addition, the working oil from the second pressure oil discharge outlet P2 will not be supplied to the second travel control valve V4 and the first control valve V3 for bulldozers.

[0113] When the travel independent valve V14 is switched to the merging position 28 , the hydraulic oil from the first pressure oil discharge port P1 and the hydraulic oil from the second pressure oil discharge port P2 merge and can be supplied to the direction switching valves DV1 to DV10 of the control valves V1 to V10 .

[0114] The third pressure oil discharge port P3 is connected to the inlet block B2 via a third discharge passage m. The third discharge passage m is branched into a first branch oil passage m1 and a second branch oil passage m2 and connected to the inlet block B2.

[0115] The first branch oil passage m1 is connected to the pressure receiving portion 14a on one side of the travel independent valve V14 via the first signal oil passage n1, and the second branch oil passage m2 is connected to the pressure receiving portion 14b on the other side of the travel independent valve V14 via the second signal oil passage n2.

[0116] The first signal oil path n1 is connected to a first detection oil path r1 , and the second signal oil path n2 is connected to a second detection oil path r2 .

[0117] The first detection oil path r1 is connected to the discharge oil path g from the first signal oil path n1 via the directional switching valve DV6 of the second bulldozing control valve V6 → the directional switching valve DV5 of the first travel control valve V5 → the directional switching valve DV4 of the second travel control valve V4 → the directional switching valve DV3 of the first bulldozing control valve V3.

[0118] The second detection oil circuit r2 is connected to the discharge oil circuit g from the second signal oil circuit n2 via the directional switching valve DV10 of the SP control valve V10 → the directional switching valve DV9 of the swing control valve V9 → the directional switching valve DV8 of the rotation control valve V8 → the directional switching valve DV7 of the boom control valve V7 → the directional switching valve DV6 of the second control valve V6 for bulldozers → the directional switching valve DV5 of the first travel control valve V5 → the directional switching valve DV4 of the second travel control valve V4 → the directional switching valve DV3 of the first control valve V3 for bulldozers → the directional switching valve DV2 of the boom control valve V2 → the directional switching valve DV1 of the working tool control valve V1.

[0119] The travel independent valve V14 is held at the merging position 28 by the force of a spring when the directional switching valves DV1 to DV10 of the control valves V1 to V10 are in neutral.

[0120] Moreover, when any of the directional switching valves DV of the second travel control valve V4, the first travel control valve V5, the first control valve for bulldozer V3, and the second control valve for bulldozer V6 is operated from the neutral position, pressure is generated in the first detection oil circuit r1 and the first signal oil circuit n1, and the travel independent valve V14 is switched from the merging position 28 to the independent position 27.

[0121] Therefore, when only traveling, when using the bulldozer device 7 while traveling, or when only using the bulldozer device 7, the working oil from the first pressure oil discharge port P1 is supplied to the second travel control valve V4 and the various direction switching valves DV of the first control valve V3 for bulldozers, and the working oil from the second pressure oil discharge port P2 is supplied to the first travel control valve V5 and the various direction switching valves DV of the first control valve V3 for bulldozers.

[0122] At this time, when any one of the direction switching valves DV10, DV9, DV8, DV7, DV2, and DV1 of the SP control valve V10, the swing control valve V9, the rotation control valve V8, the boom control valve V7, the boom control valve V2, and the working tool control valve V1 is operated from the neutral position, pressure is generated in the second detection oil circuit r2 and the second signal oil circuit n2, and the travel independent valve V14 switches from the independent position 27 to the merging position 28.

[0123] In addition, when the directional switching valves DV1~DV10 of each control valve V1~V10 are in neutral, when any one of the directional switching valves DV10, DV9, DV8, DV7, DV2, and DV1 of the SP control valve V10, the swing control valve V9, the rotation control valve V8, the boom control valve V7, the boom control valve V2, and the working tool control valve V1 is operated from the neutral position, the travel independent valve V14 is also in the confluence position 28.

[0124] Therefore, the boom 15, the arm 16, the working tool 17, the swing bracket 14, the machine body 2, and the bulldozer 7 can be operated simultaneously when the vehicle is not traveling or traveling.

[0125] Furthermore, the hydraulic system is provided with an automatic idle control system (AI system) that automatically operates an accelerator device of the prime mover E1.

[0126] The AI ​​system comprises: an AI switch (pressure switch) 29, which is connected to the first branch oil circuit m1 and the second branch oil circuit m2 of the third exhaust circuit m via a sensing oil circuit s and a shuttle valve V18; an electric actuator, which controls the speed regulator of the prime mover E1; and a control device, which controls the electric actuator, and the AI ​​switch 29 is connected to the control device.

[0127] In the AI ​​system, when the directional switching valves DV1~DV10 of each control valve V1~V10 are in neutral, no pressure is generated in the first branch oil circuit m1 and the second branch oil circuit m2, so the AI ​​switch 29 does not perform pressure sensing action. In this state, the speed governor is automatically controlled by the electric actuator, etc. to accelerate the descent to the preset idle position.

[0128] In addition, when any one of the direction switching valves DV1 to DV10 of the control valves V1 to V10 is also operated, pressure is generated in the first branch oil path m1 or the second branch oil path m2, and the pressure is sensed by the AI ​​switch 29, and the AI ​​switch 29 performs a pressure sensing operation. Then, a command signal is sent from the control device to the electric actuator, etc., and the speed governor is automatically controlled by the electric actuator, etc. to accelerate to the set acceleration position.

[0129] In addition, a load sensing system is adopted in the hydraulic system.

[0130] The load sensing system of the present embodiment comprises a pressure compensating valve V11 provided in each control valve V1 to V10, a flow compensating piston 24 for controlling the inclined plate of the first pump 21, a flow compensating valve V17 provided in the flow control unit 19, the first and second relief valves V12 and V15, and the first and second unloading valves V13 and V16. In addition, the load sensing system of the present embodiment adopts a downstream orifice type load sensing system in which the pressure compensating valve V11 is provided on the downstream side of the pressure oil supply with respect to the directional switching valves DV1 to DV10.

[0131] In the load sensing system, when a plurality of hydraulic actuators ML, MR, MT, C1 to C6 equipped in the working machine 1 are operated simultaneously, the pressure compensation valve V11 functions as a load adjustment between the hydraulic actuators ML, MR, MT, C1 to C6, and causes a pressure loss of the pressure difference amount with the maximum load pressure to be generated in the control valves V1 to V10 on the low load pressure side, and can flow (distribute) a flow rate corresponding to the operation amount of the spool valves of the direction switching valves DV1 to DV10 regardless of the magnitude of the load. That is, the load sensing system controls the first pump 21 so that the pressure difference obtained by subtracting the maximum load pressure among the plurality of hydraulic actuators ML, MR, MT, C1 to C6 from the discharge pressure of the first pump 21 becomes a constant pressure.

[0132] The load sensing system controls the discharge amount of the first pump 21 according to the load pressure of each hydraulic actuator ML, MR, MT, and C1 to C6 provided in the working machine 1 so that the hydraulic power required by the load is discharged from the first pump 21, thereby saving power and improving operability.

[0133] The load sensing system of this embodiment will be described in more detail.

[0134] The load sensing system comprises: a PLS signal oil circuit w, which transmits the highest load pressure among the load pressures of each control valve V1 to V10 as a PLS signal pressure to the flow compensation valve V17; and a PPS signal oil circuit x, which transmits the discharge pressure of the first pump 21 as a PPS signal pressure to the flow compensation valve V17.

[0135] The PLS signal oil circuit w is set from the first outlet block B1 to the valve body of the working tool control valve V1 → the valve body of the boom control valve V2 → the valve body of the first control valve V3 for bulldozers → the valve body of the second travel control valve V4, and crosses the travel independent valve V14 to the valve body of the first travel control valve V5 → the valve body of the second control valve V6 for bulldozers → the valve body of the boom control valve V7 → the valve body of the swing control valve V8 → the valve body of the swing control valve V9 → the valve body of the SP control valve V10 → the second outlet block B3. The PLS signal oil circuit w is connected to the pressure compensation valve V11 in each control valve via the load transfer line y.

[0136] In addition, the PLS signal oil passage w is connected from the second outlet block B3 to one side of the spool of the flow compensation valve V17 , and the PPS signal pressure acts on one side of the spool of the flow compensation valve V17 .

[0137] Furthermore, the PLS signal oil passage w is connected to the first unload valve V13 and the drain oil passage g in the first outlet block B1 , and is connected to the second unload valve V16 and the drain oil passage g in the second outlet block B3 .

[0138] When the independent driving valve V14 is in the merging position 28, the pipeline w1 from the independent driving valve V14 to the first outlet block B1 of the PLS signal oil circuit w is connected with the pipeline w2 from the independent driving valve V14 to the second outlet block B3. When the independent driving valve V14 switches from the merging position 28 to the independent position 27, the PLS signal oil circuit w is blocked by the independent driving valve V14.

[0139] Thus, when the travel independent valve V14 is in the independent position 27 , the PLS signal oil passage w is divided into a passage w1 supplied with hydraulic oil from the first pressure oil outlet P1 and a passage w2 supplied with pressure oil from the second pressure oil outlet P2 .

[0140] The PPS signal oil circuit x is set from the travel independent valve V14 to the other side of the slide valve of the flow compensation valve V17. The PPS signal oil circuit x is constructed so that when the travel independent valve V14 is in the merging position 28, it is connected to the second pressure oil supply circuit e via the connecting oil circuit z, and the PPS signal pressure (the discharge pressure of the first pump 21) acts on the other side of the slide valve of the flow compensation valve V17. When the travel independent valve V14 is switched to the independent position 27, the PPS signal oil circuit x is connected to the discharge oil circuit g via the pressure relief oil circuit q, and the PPS signal pressure becomes zero.

[0141] Furthermore, a spring 30 and a differential pressure piston 31 for applying a control differential pressure to the flow compensation valve V17 are provided on the spool side of the flow compensation valve V17 .

[0142] In the hydraulic system of the above structure, when the direction switching valves DV1 to DV10 of the control valves V1 to V10 are in the neutral position, the travel independent valve V14 is in the merging position 28, at which time, the flow path end side of the first pressure oil supply path d is blocked by the first unloading valve V13 and the flow path end side of the second pressure oil supply path e is blocked by the second unloading valve V16. Therefore, the discharge pressure (PPS signal pressure) of the first pump 21 rises, and when the difference between the PPS signal pressure and the PLS signal pressure (zero at this time) is greater than the control pressure difference, the first pump 21 is flow-controlled in the direction of reducing the discharge amount, and the first and second unloading valves V16 are opened to cause the discharge oil from the first pump 21 to fall into the working oil tank T2.

[0143] Therefore, in this state, the discharge pressure of the first pump 21 becomes the pressure set by the first and second unloading valves V13 and V16, and the discharge flow rate of the first pump 21 becomes the minimum discharge flow rate.

[0144] Next, the case of simultaneously operating any two or more of the boom cylinder C3, arm cylinder C4, work tool cylinder C5, swing cylinder C2, rotary motor MT, and hydraulic attachments, or the case of simultaneously operating one or more of them and any one or more of the left and right travel motors ML, MR, and bulldozer cylinder C1 is described.

[0145] In this case, the travel independent valve V14 is in the converging position 28, so that the maximum load pressure acting on the operated hydraulic actuators ML, MR, MT, C1 to C6 becomes the PLS signal pressure, and the PPS signal pressure - PLS signal pressure becomes the control pressure difference (so that the difference between the PPS signal pressure and the PLS signal pressure is maintained at a set value), thereby automatically controlling the discharge pressure (discharge flow) of the first pump 21.

[0146] That is, when the unloading flow through the first and second unloading valves V13 and V16 becomes zero, the discharge flow of the first pump 21 begins to increase, and according to the operation amount of the operated control valve, the entire amount of the discharge oil of the first pump 21 flows to the operated hydraulic actuators ML, MR, MT, C1~C6.

[0147] In addition, through the pressure compensation valve V11, the front and rear pressure difference of the sliding valve of the directional switching valve DV1~DV10 of the operated control valve V1~V10 becomes constant, regardless of the difference in the size of the load acting on the operated hydraulic actuators ML, MR, MT, C1~C6, and the discharge flow of the first pump 21 is diverted to each operated hydraulic actuator ML, MR, MT, C1~C6 by an amount corresponding to the operation amount.

[0148] When the required flow rate of the hydraulic actuators ML, MR, MT, C1 to C6 exceeds the maximum discharge flow rate of the first pump 21, the discharge oil of the first pump 21 is proportionally distributed to the operated hydraulic actuators ML, MR, MT, C1 to C6.

[0149] In the above case, simultaneous operations (complex operations) can be performed with an efficient system.

[0150] When earthmoving operations are performed by the bulldozer 7 while traveling, the travel independent valve V14 is switched to the independent position 27, through which the connecting path j and the PLS signal oil path w are cut off. In addition, the PPS signal oil path x is connected to the discharge oil path g via the pressure relief oil path q, and the PPS signal pressure becomes zero.

[0151] Therefore, the hydraulic oil from the first pressure oil discharge port P1 flows to the second travel control valve V4 and the first bulldozer control valve V3, but does not flow to the first travel control valve V5 and the second bulldozer control valve V6. In addition, the hydraulic oil from the second pressure oil discharge port P2 flows to the first travel control valve V5 and the second bulldozer control valve V6, but does not flow to the second travel control valve V4 and the first bulldozer control valve V3. Moreover, since the PPS signal pressure is zero, the swash plate angle of the first pump 21 becomes MAX and discharges the maximum flow rate.

[0152] like Figure 8As shown, the proportional solenoids so1 to so10 of the directional switching valves DV1 to DV10 are connected to the control device U1. The directional switching valves DV1 to DV10 (the control valves V1 to V10) are pilot operated by the pilot control pressure corresponding to the control signal (the current value supplied to the proportional solenoids so1 to so10) sent from the control device U1 to the proportional solenoids so1 to so10, so as to control the direction and flow rate of the working oil relative to the hydraulic actuators ML, MR, MT, C1 to C6 that are the controlled objects. That is, the control valves V1 to V10 are pilot operated by the pilot control pressure controlled by the control signal sent from the control device U1. In other words, the control valves V1 to V10 are controlled according to the current value supplied by the control device U1.

[0153] The control device U1 is connected to an operating member 41 (first operating tool 41A to seventh operating tool 41G) for operating each directional switching valve DV1 to DV10 (each control valve V1 to V10). The control device U1 supplies (transmits) a current value (control signal) corresponding to the operation amount of the operating member 41 to the proportional solenoids so1 to so10 of the directional switching valves DV1 to DV10 of the operation object.

[0154] The first operating tool 41A and the second operating tool 41B are provided in the operating device 1B and are constituted by, for example, handles that are gripped and operated by an operator sitting in the driver's seat 6 .

[0155] The first operating tool 41A is capable of operating two operating objects equipped on the working machine 1. For example, the first operating tool 41A is capable of operating the direction switching valve DV8 (swing motor MT) (capable of performing a swing operation on the machine body 2) and is capable of operating the direction switching valve DV7 (arm cylinder C4) (capable of performing a swing operation on the arm 16). In addition, the first operating tool 41A has a sensor (operation detection unit) 42 (first sensor 42A) for detecting the operation direction and operation amount. The first sensor 42A is connected to the control device U1. The control device U1 controls the swing control valve V8 (machine body 2) and the arm control valve V7 (arm 16) based on the detection signal from the first sensor 42A.

[0156] The second operating tool 41B can also operate two operating objects equipped on the working machine 1. For example, the second operating tool 41B can operate the direction switching valve DV2 (boom cylinder C3) (can swing the boom 15) and can operate the direction switching valve DV1 (working tool cylinder C5) (can swing the working tool 17). In addition, the second operating tool 41B has a sensor (operation detection unit) 42 (second sensor 42B) for detecting the operation direction and operation amount. The second sensor 42B is connected to the control device U1. The control device U1 controls the boom control valve V2 (boom 15) and the working tool control valve V1 (working tool 17) according to the detection signal from the second sensor 42B.

[0157] The third operating tool 41C is provided on the operating device 1B, and is composed of a rod, for example. The third operating tool 41C can operate the direction switching valve DV3 and the direction switching valve DV6 (bulldozer cylinder C1) (can operate the bulldozer device 7). In addition, the third operating tool 41C has a sensor 42 (third sensor 42C) for detecting the operation direction and the operation amount. The third sensor 42C is connected to the control device U1. The control device U1 controls the first control valve V3 for bulldozer and the second control valve V6 for bulldozer (bulldozer device 7) based on the detection signal from the third sensor 42C.

[0158] The fourth operating tool 41D and the fifth operating tool 41E are provided on, for example, a floor portion in front of the driver's seat 6 , and are constituted by pedals operated by an operator's stepping operation.

[0159] The fourth operating tool 41D can operate the direction switching valve DV5 (first travel motor ML) (can operate the first travel device 3L). In addition, the fourth operating tool 41D has a sensor 42 (fourth sensor 42D) for detecting the operation direction and the operation amount. The fourth sensor 42D is connected to the control device U1. The control device U1 controls the first travel control valve V5 (first travel device 3L) based on the detection signal from the fourth sensor 42D.

[0160] The fifth operating tool 41E can operate the direction switching valve DV4 (the second travel motor MR) (can operate the second travel device 3R). In addition, the fifth operating tool 41E has a sensor 42 (fifth sensor 42E) for detecting the operation direction and the operation amount. The fifth sensor 42E is connected to the control device U1. The control device U1 controls the second travel control valve V4 (the second travel device 3R) based on the detection signal from the fifth sensor 42E.

[0161] The sixth operating tool 41F is composed of, for example, a switch (a seesaw switch, a slide switch, etc.) provided on the first operating tool 41A or the second operating tool 41B. The sixth operating tool 41F can operate the direction switching valve DV9 (swing cylinder C2) (can operate the swing bracket 14). In addition, the sixth operating tool 41F has a sensor 42 (sixth sensor 42F) for detecting the operation direction and the operation amount. The sixth sensor 42F is connected to the control device U1. The control device U1 controls the swing control valve V9 (swing bracket 14) based on the detection signal from the sixth sensor 42F.

[0162] The seventh operating tool 41G is composed of, for example, a switch (a seesaw switch, a slide switch, etc.) provided on the first operating tool 41A or the second operating tool 41B. The seventh operating tool 41G can operate the direction switching valve DV10 (a hydraulic actuator of a hydraulic attachment) (can operate the hydraulic attachment as a working tool). In addition, the seventh operating tool 41G has a sensor 42 (a seventh sensor 42G) for detecting the operation direction and the operation amount. The seventh sensor 42G is connected to the control device U1. The control device U1 controls the SP control valve V10 (hydraulic attachment) based on the detection signal from the seventh sensor 42G.

[0163] The structure of the sensor 42 (the first sensor 42A to the seventh sensor 42G) is not particularly limited, and for example, a potentiometer or the like may be used.

[0164] The slide valves of the directional switching valves DV1 to DV10 are operated in proportion to the operation amount of the operating members 41 that operate the directional switching valves DV1 to DV10 (the control valves V1 to V10), and the hydraulic oil in an amount proportional to the amount of operation of the directional switching valves DV1 to DV10 is supplied to the hydraulic actuators ML, MR, MT, C1 to C6 of the controlled objects. That is, the working speed of the operated object (controlled object) can be changed in proportion to the operation amount of the operating members 41.

[0165] As described above, the control valves V1 to V10 are operated by operating the operating member 41, thereby operating the corresponding hydraulic actuators ML, MR, MT, C1 to C6. Furthermore, the driving parts (machine body 2, travel device 3, bulldozer 7, boom 15, arm 16, working tool 17, hydraulic attachment) are driven by the hydraulic actuators ML, MR, MT, C1 to C6.

[0166] Figure 8 A first embodiment of the control system is shown.

[0167] like Figure 8 As shown, the control device U1 includes a control unit Ua and a boom flow rate suppressing unit Ub.

[0168] The control unit Ua controls the boom control valve (first control valve) V2 when the boom cylinder (first hydraulic actuator) C3 is operated independently (independently). In other words, the control unit Ua controls the boom control valve V2 when the boom cylinder C3 is operated independently.

[0169] The boom flow suppression unit Ub controls the boom control valve V2 when the boom cylinder (first hydraulic actuator) C3 and the arm cylinder (second hydraulic actuator) C4 are operated simultaneously (compound operation). In other words, the boom flow suppression unit Ub controls the boom control valve V2 when the boom control valve V2 and the arm control valve V7 are operated in combination. In detail, the boom flow suppression unit Ub controls the flow rate (working oil flow rate) of the working oil supplied from the boom control valve V2 to the boom cylinder C3 when the boom cylinder C3 (boom control valve V2) is operated while the arm cylinder C4 (arm control valve V7) is being operated.

[0170] Fig. 9 The graph shows the relationship between the operation amount of the operation member 41 (second operation tool 41B) and the flow rate of hydraulic oil when the horizontal axis represents the operation amount of the operation member 41 and the vertical axis represents the flow rate of hydraulic oil supplied from the boom control valve V2 to the boom cylinder C3 .

[0171] Fig. 9 The first line 50 in FIG. 4 shows that the control unit Ua controls the flow rate of hydraulic oil supplied from the boom control valve V2 to the boom cylinder C3 according to the operation amount of the operation member 41. That is, it shows the change in the flow rate of hydraulic oil corresponding to the operation amount of the boom cylinder C3 when the boom cylinder C3 is operated alone.

[0172] Fig. 9 The second line 51 in the figure shows that the boom flow suppression unit Ub controls the flow of the working oil supplied from the boom control valve V2 to the boom cylinder C3 relative to the operation amount of the operating component 41. That is, it shows the change in the working oil flow corresponding to the operation amount of the boom cylinder C3 when the boom cylinder C3 and the boom cylinder C4 are operated in combination.

[0173] Fig. 9 Reference numeral 52 in the figure denotes the amount of change in the flow rate of the hydraulic oil supplied from the boom control valve V2 to the boom cylinder C3 with respect to the change in the operation amount of the boom cylinder C3 when the boom cylinder C3 is operated alone.

[0174] Fig. 9 Reference numeral 53 in the figure indicates the amount of change in the flow rate of hydraulic oil supplied from the boom control valve V2 to the boom cylinder C3 with respect to the change in the operation amount of the boom cylinder C3 when the arm cylinder C4 and the boom cylinder C3 are operated in combination.

[0175] from Fig. 9It can be seen that the second line 51 has a smaller inclination than the first line 50, and the change 53 is smaller than the change 52. That is, when the control device U1 performs a combined operation on the boom cylinder (second hydraulic actuator) C4 and the boom cylinder (first hydraulic actuator) C3, the control device U1 reduces the change 53 of the flow rate of the working oil supplied from the boom control valve (first control valve) V2 to the boom cylinder (first hydraulic actuator) C3 relative to the change in the operation amount of the boom cylinder (first hydraulic actuator) C3, compared with the case where the boom cylinder (first hydraulic actuator) C3 is operated alone.

[0176] In addition, if Fig. 9 As shown, in the first embodiment, when the arm cylinder C4 and the boom cylinder C3 are operated in combination, the boom flow rate suppression unit Ub reduces the flow rate of the hydraulic oil supplied from the boom control valve V2 to the boom cylinder C3 , thereby making the change amount 53 smaller than the change amount 52 .

[0177] In detail, from Fig. 9 It can be seen from the first line 50 and the second line 51 in that when the boom cylinder C3 (boom control valve V2) is operated alone and when the arm cylinder C4 (arm control valve V7) and the boom cylinder C3 (boom control valve V2) are operated in combination, when the operation amount of the operating member 41 (the second operating tool 41B) is the same, the flow rate of the working oil supplied from the boom control valve V2 to the boom cylinder C3 when the arm cylinder C4 (arm control valve V7) and the boom cylinder C3 (boom control valve V2) are operated in combination is less than when the boom cylinder C3 (boom control valve V2) is operated alone. That is, when the arm cylinder C4 (arm control valve V7) and the boom cylinder C3 (boom control valve V2) are operated in combination, the flow rate of the working oil supplied to the boom cylinder C3 is reduced relative to the operation amount of the operating member 41 (the second operating tool 41B).

[0178] That is, the boom flow suppression unit Ub supplies working oil with a flow rate less than the flow rate of working oil controlled by the control unit Ua from the boom control valve V2 to the boom cylinder C3 for the same operation amount of the operating component 41. Therefore, when the boom cylinder C3 (boom control valve V2) is operated while the boom cylinder C4 (boom control valve V7) is being operated, the boom flow suppression unit Ub reduces the flow rate of working oil supplied from the boom control valve V2 to the boom cylinder C3. In other words, the boom flow suppression unit Ub supplies working oil with a flow rate less than the flow rate of working oil controlled by the control unit Ua according to the operation amount from the boom control valve V2 to the boom cylinder C3 for the same operation amount of the operating component 41 (second operating tool 41B).

[0179] In this embodiment, the flow rate of the working oil supplied from the boom control valve V2 to the boom cylinder C3 is reduced by reducing the pilot control pressure controlled by the control signal sent from the control device U1 to the boom control valve V2. In other words, the flow rate of the working oil supplied from the boom control valve V2 to the boom cylinder C3 is reduced by reducing the current value supplied from the control device U1 to the boom control valve V2.

[0180] However, as a case where the boom 15 (boom cylinder C3) and the arm 16 (arm cylinder C4) are operated in combination (simultaneously), there is a so-called horizontal pulling operation (horizontal pulling operation). The horizontal pulling operation is to move the claw 17a (refer to Figure 1 ) is in contact with the ground, while the boom 15 is raised by swinging the boom 16 in the boom loading direction D1, the bucket 17 is moved horizontally to level the ground. In this horizontal pulling operation, proficiency is required in order to perform micro-operations on the boom 15. That is, generally, if the boom 16 is moved, the balance of the machine body 2 changes greatly, thereby changing the amount of operation of the operating component 41 (second operating tool 41B) for operating the boom 15, so proficiency is required. In addition, the same can be said when the boom 15 is lowered while the boom 16 is swung in the boom unloading direction D2 while the front end claw 17a of the bucket 17 is in contact with the ground.

[0181] In the first embodiment, when the boom 15 is operated while the arm 16 is operated, the pilot control pressure is reduced compared to the case where the boom 15 is operated alone, and the flow rate of the hydraulic oil supplied from the boom control valve V2 to the boom cylinder C3 is reduced, thereby suppressing the rising speed of the boom 15, and the boom 15 can be operated stably, and the front claw 17a of the bucket 17 can be easily moved horizontally. As a result, when the boom 15 is raised while the arm 16 is swung in the arm loading direction D1, or when the boom 15 is lowered while the arm 16 is swung in the arm unloading direction D2, the boom 15 can be easily operated.

[0182] In the first embodiment, for example, when the operation amount of the boom cylinder C3 and the operation amount of the arm cylinder C4 are the same and the speed of the arm 16 is slower than the speed of the boom 15, when performing a horizontal pulling operation, the movement of the boom 15 and the arm 16 is coordinated by reducing the speed of the boom 15, so that the horizontal pulling operation can be performed well.

[0183] In addition, since the boom 15 can be prevented from swinging greatly, the body 2 can be prevented from swinging. In addition, when the boom 15 is operated while the boom 16 is operated, the flow rate of the hydraulic oil supplied from the boom control valve V2 to the boom cylinder C3 is reduced, and accordingly, the flow rate of the hydraulic oil is diverted to the boom cylinder C4, thereby ensuring the moving speed of the bucket 17, and the boom characteristics become stable, and the body 2 is stabilized. In addition, since the load sensing system is provided, the intermediate flow characteristics are stable, so even if the speed of the boom 15 is reduced by reducing the flow rate of the hydraulic oil by reducing the pilot control pressure, stable operation can be performed.

[0184] In addition, in the present embodiment, the boom flow suppressing unit Ub controls the boom control valve V2 to reduce the flow rate of the working oil supplied from the boom control valve V2 to the boom cylinder C3 when the boom cylinder C3 is operated while the arm cylinder C4 is being operated. However, the present invention is not limited thereto, and the boom cylinder (first hydraulic actuator) C3 may be operated while another hydraulic actuator (second hydraulic actuator) AC different from the boom cylinder (first hydraulic actuator) C3 is being operated to reduce the flow rate of the working oil supplied from the boom control valve (first control valve) V2 to the boom cylinder C3. That is, the boom flow suppressing unit Ub controls the flow rate of the working oil supplied from the boom control valve V2 to the boom cylinder C3 when the boom cylinder C3 is operated while another hydraulic actuator AC different from the boom cylinder C3 is being operated (when the boom cylinder C3 and another hydraulic actuator AC different from the boom cylinder C3 are operated in combination).

[0185] The other hydraulic actuator (second hydraulic actuator) AC different from the boom cylinder (first hydraulic actuator) C3 may be, in addition to the arm cylinder C4, the travel motor M1, the slewing motor MT, the bulldozer cylinder C1, the swing cylinder C2, the work tool cylinder C5, and the attachment actuator C6. In addition, even if the other hydraulic actuator AC different from the boom cylinder C3 is a hydraulic actuator other than the arm cylinder C4, that is, the travel motor M1, the slewing motor MT, the bulldozer cylinder C1, the swing cylinder C2, the work tool cylinder C5, and the attachment actuator C6, it is possible to expect the boom characteristics to be smooth and the machine body 2 to be stable.

[0186] Even when other hydraulic actuators AC other than the boom cylinder C3 and the arm cylinder C4 are operated in combination, the actions of the boom 15 and the components driven by the other hydraulic actuators AC can be coordinated.

[0187] In the above-mentioned hydraulic system, each control valve V1~V10 (each directional switching valve DV1~DV10) is composed of a pilot-operated proportional solenoid valve, and the control device U1 controls the pilot control pressure by controlling the current value supplied to each control valve V1~V10, thereby controlling the structure of each control valve V1~V10, but it is not limited to this.

[0188] For example, Fig.10 As shown, each control valve V1~V10 is composed of a pilot-operated switching valve, which is pilot-operated by a pilot control pressure acting on a pair of pilot pressure-receiving parts Va1, Va2, and a pair of proportional solenoid valves V21, V22 controlled by the control device U1 are provided. It can also be constructed so that the pilot control pressure is supplied from the proportional solenoid valve V21 on one side to the pilot pressure-receiving part Va1 on one side, and the pilot control pressure is supplied from the proportional solenoid valve V22 on the other side to the pilot pressure-receiving part Va2 on the other side, thereby controlling the direction and flow rate of the working oil relative to the hydraulic actuators MT, ML, MR, C1~C6.

[0189] In addition, if Fig.11 As shown, each of the control valves V1 to V10 may be constituted by a proportional electromagnetic directional / flow control valve in which a spool is directly driven by a proportional solenoid so11 supplied with electric current from the control device U1.

[0190] Fig.12 A second embodiment of the control system is shown.

[0191] like Fig.12 As shown in FIG. 1 , a changeover switch SW is connected to the control device U1 . The changeover switch SW is a switch for switching to a crane mode for lifting a hoisted object using a hook provided on the bucket 17 .

[0192] The control device U1 includes a control unit Ua, a boom flow rate increasing unit Uc, and a function shutoff unit Ud.

[0193] The control unit Ua controls the boom control valve (first control valve) V2 when operating the boom cylinder (first hydraulic actuator) C3 alone. In other words, the control unit Ua controls the boom control valve V2 when operating the boom control valve V2 alone.

[0194] When the boom cylinder (first hydraulic actuator) C3 and the arm cylinder (second hydraulic actuator) C4 are operated simultaneously (compound operation), the boom flow increment unit Uc controls the boom control valve V2. In other words, when the boom control valve V2 and the arm control valve V7 are operated in a compound manner, the boom flow increment unit Uc controls the boom control valve V2. Specifically, when the arm cylinder C4 (arm control valve V7) and the boom cylinder C3 (boom control valve V2) are operated in a compound manner, the boom flow increment unit Uc controls the flow of the working oil supplied from the boom control valve V2 to the boom cylinder C3.

[0195] In addition, in the second embodiment, the second hydraulic actuator is not limited to the boom cylinder C4, and the second hydraulic actuator can be any other hydraulic actuator (boom cylinder C4, travel motor M1, rotation motor MT, bulldozer cylinder C1, swing cylinder C2, work tool cylinder C5 and attachment actuator C6) AC that is different from the boom cylinder C3.

[0196] When the boom cylinder C3 is being operated alone in the direction of raising the boom 15, the function cut-off unit Ud makes the boom flow rate increasing unit Uc inoperative when the arm cylinder C4 (another hydraulic actuator AC different from the boom cylinder C3) is being operated. In the present embodiment, the function cut-off unit Ud is operative when the crane mode is switched by the switching switch SW. When the boom cylinder C3 and the arm cylinder C4 are operated in combination, the boom flow rate increasing unit Uc increases the flow rate of the working oil supplied to the boom cylinder C3 to increase the speed of the boom 15. However, when a crane operation is being performed, for example, when the boom 16 is being operated, if the speed of the boom 15 increases, it may be difficult to perform a stable crane operation. Therefore, when the crane mode is selected, the boom flow rate increasing unit Uc is made inoperative. As a result, when the crane operation is being performed, even if the arm cylinder C4 (another hydraulic actuator AC different from the boom cylinder C3) is operated, the rising speed of the boom 15 does not change, and a stable lifting operation can be performed.

[0197] In addition, as described later, when the operating component 41 (the second operating tool 41B) is fully operated (the operating component 41 is operated to the end of the stroke) and the boom cylinder C3 is being operated, when the boom cylinder C3 is operated alone, and when a combined operation is being performed on the boom cylinder C3 and the boom cylinder C4 (other hydraulic actuator AC), the flow rate of the working oil supplied to the boom cylinder C3 is also the same, so the function of the function cut-off portion Ud can be performed outside of the full operation of the operating component 41.

[0198] Fig.13It is a graph showing the relationship between the operation amount of the operating component 41 (the second operating tool 41B) and the flow rate of the working oil when the horizontal axis is the operation amount of the operating component 41 (the second operating tool 41B) and the vertical axis is the flow rate of the working oil supplied from the boom control valve V2 to the boom cylinder C3 (the current value supplied to the proportional solenoid so2 = the pilot control pressure for the pilot operation of the boom control valve V2).

[0199] Fig.13 The third line 55 shows that the control unit Ua controls the flow rate of hydraulic oil supplied from the boom control valve V2 to the boom cylinder C3 according to the operation amount of the operation member 41. That is, it shows the change of the hydraulic oil flow rate corresponding to the operation amount of the boom cylinder C3 when the boom cylinder C3 is operated alone.

[0200] Fig.13 The fourth line 56 in the figure shows the situation in which the boom flow increment unit Uc controls the flow of the working oil supplied from the boom control valve V2 to the boom cylinder C3 relative to the operation amount of the operating component 41. That is, it shows the change in the working oil flow corresponding to the operation amount of the boom cylinder C3 when the boom cylinder C3 and the stick cylinder C4 (other hydraulic actuator AC) are operated in combination.

[0201] exist Fig.13 In the diagram, the flow rate of the working oil increases as it moves away from the origin of the diagram. In addition, the operation amount of the operating member 41 is 0 (not operated) at the origin of the diagram, and increases as it moves away from the origin. Therefore, the origin side of the diagram is the start side 57 of the boom control valve V2.

[0202] From the operation amount G0 of 0 to the operation amount G1, the working oil flow is 0, and it is a non-sensing area in which the boom 15 does not move even if the operating part 41 is operated. At the operation amount G1, the working oil flow suddenly rises to H1 or H2. In the third line 55, the working oil flow under the operation amount G1 is H1, and in the fourth line 56, the working oil flow under the operation amount G1 is H2 which is higher than H1. That is, in the case of a combined operation of the boom cylinder C4 (other hydraulic actuators AC) and the boom cylinder C3, the setting of the starting side 57 of the boom control valve relative to the working oil flow of the operation amount of the boom cylinder C3 is set higher than when the boom cylinder C3 is operated alone.

[0203] In addition, the third line 55 and the fourth line 56 are inclined to the upper right as the operation amount G1 is directed toward the operation amount G2 before the full operation, and the hydraulic oil flow rate converges to H3 at the operation amount G2. That is, the flow rate H2 on the start side 57 of the fourth line 56 is higher than the flow rate H1 on the start side of the third line 55, and the inclination of the fourth line 56 is smaller than that of the third line 55. Therefore, as the operation amount of the boom cylinder C3 increases, the difference 58 (the interval between the third line 55 and the fourth line 56) between the hydraulic oil flow rates with respect to the operation amount of the boom cylinder C3 during the combined operation and the single operation becomes smaller.

[0204] Furthermore, at the operation amount G2, the hydraulic oil flow rate increases all at once from H3 to the maximum flow rate H4, and during the operation from the operation amount G2 to the operation amount G3 (the operation amount when the operating member 41 is fully operated), the hydraulic oil flow rate is the maximum flow rate H4.

[0205] In the second embodiment, the third line 55 and the fourth line 56 are characteristic lines of the intermediate operation area from the operation amount G1 to the operation amount G2. The third line 55 and the fourth line 56 may also be characteristic lines from the operation amount G1 to the operation amount G3. In this case, the end position of the third line 55 and the fourth line 56 becomes the position of the maximum flow rate H4.

[0206] Fig.13 Reference numeral 61 indicates the amount of change in the flow rate of hydraulic oil supplied from the boom control valve V2 to the boom cylinder C3 with respect to the change in the operation amount of the boom cylinder C3 when the boom cylinder C3 is operated alone.

[0207] Fig.13 Reference numeral 62 indicates a change in the flow rate of hydraulic oil supplied from the boom control valve V2 to the boom cylinder C3 with respect to a change in the operation amount of the boom cylinder C3 when the arm cylinder C4 (other hydraulic actuator AC) and the boom cylinder C3 are operated in combination.

[0208] like Fig.13 It can be seen that the change 62 is smaller than the change 61. That is, when the control device U1 performs a combined operation on the boom cylinder C4 (other hydraulic actuator AC) and the boom cylinder C3, the control device U1 reduces the change 62 of the flow rate of the working oil supplied from the boom control valve V2 to the boom cylinder C3 relative to the change in the operation amount of the boom cylinder C3, compared with when the boom cylinder C3 is operated alone.

[0209] In the second embodiment, when the boom flow increment unit Uc performs a combined operation on the boom cylinder C4 (other hydraulic actuator AC) and the boom cylinder C3, the starting side 57 of the boom control valve V2 of the working oil flow relative to the operation amount of the boom cylinder C3 is set higher than when the boom cylinder C3 is operated alone, and as the operation amount of the boom cylinder C3 increases, the change 62 is made smaller than the change 61 by reducing the difference 58 between the change in the working oil flow relative to the operation amount of the boom cylinder C3 during the combined operation and during the single operation.

[0210] from Fig.13 It can be seen from the third line 55 and the fourth line 56 in that when the boom cylinder C3 (boom control valve V2) is operated alone and when the arm cylinder C4 (arm control valve V7) and the boom cylinder C3 (boom control valve V2) are operated in combination, when the operation amount of the operating member 41 (the second operating tool 41B) is the same, the flow rate of the working oil supplied from the boom control valve V2 to the boom cylinder C3 is greater when the arm cylinder C4 (arm control valve V7) and the boom cylinder C3 (boom control valve V2) are operated in combination than when the boom cylinder C3 (boom control valve V2) is operated alone. That is, when the arm cylinder C4 (arm control valve V7) and the boom cylinder C3 (boom control valve V2) are operated in combination, the flow rate of the working oil supplied to the boom cylinder C3 increases relative to the operation amount of the operating member 41 (the second operating tool 41B).

[0211] That is, the boom flow increment unit Uc causes the boom control valve V2 to supply the boom cylinder C3 with a flow rate greater than the flow rate of the working oil controlled by the control unit Ua for the same operation amount of the operating component 41. Therefore, when the boom cylinder C3 (boom control valve V2) is operated while the boom cylinder C4 (boom control valve V7) is operated, the boom flow increment unit Uc increases the flow rate of the working oil supplied from the boom control valve V2 to the boom cylinder C3. In other words, the boom flow increment unit Uc causes the boom control valve V2 to supply the boom cylinder C3 with a flow rate greater than the flow rate of the working oil controlled by the control unit Ua according to the operation amount for the operating component 41 (second operating tool 41B).

[0212] In the second embodiment, the flow rate of the working oil supplied from the boom control valve V2 to the boom cylinder C3 is increased by increasing the pilot control pressure controlled by the control signal sent from the control device U1 to the boom control valve V2. In other words, the flow rate of the working oil supplied from the boom control valve V2 to the boom cylinder C3 is increased by increasing the current value supplied from the control device U1 to the boom control valve V2.

[0213] In the second embodiment, when the boom 15 is operated while the arm 16 is operated, the pilot control pressure is increased compared to the case where the boom 15 is operated alone, and the flow rate of the hydraulic oil supplied from the boom control valve V2 to the boom cylinder C3 is increased, thereby increasing the raising speed of the boom 15, and the boom 15 can be operated stably, and the front claw 17a of the bucket 17 can be easily moved horizontally. As a result, when the boom 15 is raised while the arm 16 is swung in the arm loading direction D1, or when the boom 15 is lowered while the arm 16 is swung in the arm unloading direction D2, the boom 15 can be easily operated.

[0214] In the second embodiment, for example, when the operation amount of the boom cylinder C3 and the operation amount of the arm cylinder C4 are the same operation amount and the speed of the arm 16 is faster than the speed of the boom 15, when performing a horizontal pulling operation, by increasing the speed of the boom 15, the movement of the boom 15 and the arm 16 can be coordinated, and the horizontal pulling operation can be performed well. In detail, when the speed of the arm 16 is set faster to improve the working capacity, if the horizontal pulling operation is performed, the claw 17a at the front end of the bucket 17 may sink into the soil (the claw 17a falls) when the boom 15 and the arm 16 are started. In such a case, by increasing the speed of the boom 15, the movement of the boom 15 and the arm 16 can be coordinated, and the horizontal pulling operation can be performed well.

[0215] In the above-mentioned first embodiment, for example, when the operation amount of the boom cylinder C3 and the operation amount of the arm cylinder C4 are the same operation amount and the speed of the arm 16 is slower than the speed of the boom 15, it is effective when performing horizontal pulling operations. In the second embodiment, for example, when the operation amount of the boom cylinder C3 and the operation amount of the arm cylinder C4 are the same operation amount and the speed of the arm is faster than the speed of the boom 15, it is effective when performing horizontal pulling operations.

[0216] In the second embodiment, it is also possible to configure such that when a composite operation is being performed on other hydraulic actuators (second hydraulic actuators) AC different from the boom cylinder C3, that is, other hydraulic actuators AC other than the boom cylinder C4 and the boom cylinder C3, the flow rate of the working oil supplied from the boom control valve V2 to the boom cylinder C3 is increased. That is, the boom flow rate increasing unit Uc controls the flow rate of the working oil supplied from the boom control valve V2 to the boom cylinder C3 when a composite operation is being performed on the boom cylinder C3 and other hydraulic actuators AC different from the boom cylinder C3.

[0217] Furthermore, even when other hydraulic actuators AC other than the boom cylinder C3 and the arm cylinder C4 are operated in combination, the actions of the boom 15 and the components driven by the other hydraulic actuators AC can be coordinated.

[0218] In addition, a boom flow suppression unit Ub and a boom flow increasing unit Uc are provided in the control device U1, and it is possible to switch between a situation where the boom flow increasing unit Uc is inactive and the boom flow suppression unit Ub is active, and a situation where the boom flow suppression unit Ub is inactive and the boom flow increasing unit Uc is active, according to the working machine 1 carried.

[0219] In addition, in the second embodiment, it can also be configured as follows: Fig.10 As shown, each control valve V1 to V10 is composed of a pilot-operated switching valve, and a pair of proportional solenoid valves V21 and V22 controlled by a control device U1 are provided. A pilot control pressure is supplied from one proportional solenoid valve V21 to one pilot pressure receiving portion Va1, and a pilot control pressure is supplied from the other proportional solenoid valve V22 to the other pilot pressure receiving portion Va2. In addition, as shown in FIG. Fig.11 As shown, each of the control valves V1 to V10 may be constituted by a proportional electromagnetic directional / flow control valve in which a spool is directly driven by a proportional solenoid so11 supplied with electric current from the control device U1.

[0220] Fig.14 A control system according to a third embodiment is shown.

[0221] like Fig.14 As shown, the control device U1 includes a control unit Ua and an actuator flow rate suppressing unit Ue.

[0222] The control unit Ua controls the actuator control valve (first control valve) AV that controls the other hydraulic actuator AC1 when the other hydraulic actuator (first hydraulic actuator) AC1 that is different from the travel motor (second hydraulic actuator) M1 is operated independently. In other words, the control unit Ua controls the actuator control valve AV when the actuator control valve (first control valve) AV is operated independently.

[0223] When the travel motor (second hydraulic actuator) M1 and another hydraulic actuator (first hydraulic actuator) AC1 are operated in combination, the actuator flow suppressor Ue controls the actuator control valve (first control valve) AV. In other words, when the first travel control valve V5 and the second travel control valve V4 and the actuator control valve AV that controls another hydraulic actuator AC1 are operated in combination, the actuator flow suppressor Ue controls the actuator control valve AV. The combined operation means operating at least two (or more) control valves V1 to V10 at the same time.

[0224] Specifically, when another hydraulic actuator AC1 different from the travel motor M1 is operated while the travel device 3 is being driven, the actuator flow rate suppressing unit Ue controls the flow rate of the working oil supplied from the actuator control valve AV that controls the other hydraulic actuator AC1 to the other hydraulic actuator AC1. The other hydraulic actuator (first hydraulic actuator) AC1 is, for example, a swing motor MT, a boom cylinder C3, an arm cylinder C4, and a work tool cylinder C5 operated by the first operating tool 41A and the second operating tool 41B, and the actuator control valve AV is a swing control valve V8, a boom control valve V2, an arm control valve V7, and a work tool control valve V1. That is, when a combined operation is performed on the travel device 3 (first travel control valve V5, second travel control valve V4), the working device 4 (boom control valve V2, boom control valve V7, working tool control valve V1) and the machine body 2 (swing control valve V8), the actuator flow suppression unit Ue controls the flow of working oil supplied from the actuator control valve AV to another hydraulic actuator AC1.

[0225] Furthermore, a swing cylinder C2 and an attachment actuator C6 may be added as another hydraulic actuator AC1.

[0226] Fig.15 The graph shows the relationship between the operation amount of the operation member 41 and the flow rate of hydraulic oil, with the horizontal axis representing the operation amount of the operation member 41 and the vertical axis representing the flow rate of hydraulic oil supplied from the actuator control valve AV to the corresponding other hydraulic actuator AC1 .

[0227] Fig.15 The first line 150 in FIG. 1 shows a situation where the control unit Ua controls the flow rate of the hydraulic oil supplied from the actuator control valve AV to the corresponding other hydraulic actuator AC1 in accordance with the operation amount of the operating member 41. That is, it shows the change in the flow rate of the hydraulic oil corresponding to the operation amount of the other hydraulic actuator AC1 when the other hydraulic actuator AC1 is operated alone.

[0228] Fig.15 The second line 151 in the diagram shows the situation that the actuator flow suppressor Ue controls the flow rate of the working oil supplied from the actuator control valve AV (swing control valve V8, boom control valve V2, arm control valve V7, work tool control valve V1) to the other hydraulic actuator AC (swing motor MT, boom cylinder C3, arm cylinder C4, work tool cylinder C5) with respect to the operation amount of the operating member 41. That is, it shows the change of the working oil flow rate corresponding to the operation amount of the other hydraulic actuator AC1 when the travel motor M1 and the other hydraulic actuator AC1 are operated in combination.

[0229] Fig.15Reference numeral 152 in FIG. 1 represents the amount of change in the flow rate of hydraulic oil supplied from the actuator control valve AV to the other hydraulic actuator AC1 with respect to the change in the operation amount of the other hydraulic actuator AC1 when the other hydraulic actuator AC1 is independently operated.

[0230] Fig.15 Reference numeral 153 in the figure indicates a change in the flow rate of hydraulic oil supplied from the actuator control valve AV to the other hydraulic actuator AC1 with respect to a change in the operation amount of the other hydraulic actuator AC1 when the travel motor M1 and the other hydraulic actuator AC1 are operated in combination.

[0231] from Fig.15 It can be seen that the inclination of the second line 151 is smaller than that of the first line 150, and the change 153 is smaller than the change 152. That is, when the other hydraulic actuator (first hydraulic actuator) AC1 and the travel motor (second hydraulic actuator) M1 are operated in combination, the control device U1 reduces the change 153 of the flow rate of the working oil supplied from the actuator control valve (first control valve) AV to the other hydraulic actuator (first hydraulic actuator) AC1 relative to the change in the operation amount of the other hydraulic actuator (first hydraulic actuator) AC1, compared with the case where the other hydraulic actuator (first hydraulic actuator) AC1 is operated alone.

[0232] In addition, if Fig.15 As shown, in the third embodiment, when a combined operation is performed on another hydraulic actuator AC1 and a travel motor M1, the actuator flow suppression unit Ue is used to reduce the flow of working oil supplied by the actuator control valve AV to another hydraulic actuator AC1, so that the change 153 is smaller than the change 152.

[0233] In detail, from Fig.15It can be seen from the first line 150 and the second line 151 in that when the other hydraulic actuator AC1 (actuator control valve AV) is operated individually and when the travel motor M1 (first travel control valve V5 and second travel control valve V4) and the other hydraulic actuator AC1 (actuator control valve AV) are operated in combination, when the operation amount of the operating component 41 is the same, the flow rate of the working oil supplied from the actuator control valve AV to the other hydraulic actuator AC1 is less when the travel motor M1 (first travel control valve V5 and second travel control valve V4) and the other hydraulic actuator AC1 (actuator control valve AV) are operated in combination than when the other hydraulic actuator AC1 (actuator control valve AV) is operated individually. That is, when the travel motor M1 (first travel valve V5 and second travel valve V4) and another hydraulic actuator AC1 (actuator control valve AV) are operated in combination, the flow rate of hydraulic oil supplied to another hydraulic actuator AC1 decreases relative to the operation amount of the operating member 41.

[0234] That is, the actuator flow suppressing unit Ue supplies the working oil from the actuator control valve AV to the other hydraulic actuator AC1 at a flow rate less than the flow rate of the working oil controlled by the control unit Ua for the same operation amount of the operating member 41. In addition, when the other hydraulic actuator AC1 is operated while the travel motor M1 is being operated, the actuator flow suppressing unit Ue reduces the flow rate of the working oil supplied from the actuator control valve AV to the other hydraulic actuator AC1. In other words, the actuator flow suppressing unit Ue supplies the working oil from the actuator control valve AV to the other hydraulic actuator AC1 at a flow rate less than the flow rate of the working oil controlled by the control unit Ua according to the operation amount for the operating member 41.

[0235] In the present embodiment, the flow rate of the working oil supplied from the actuator control valve AV to the other hydraulic actuator AC1 is reduced by reducing the pilot control pressure controlled by the control signal sent from the control device U1 to the actuator control valve AV. In other words, the flow rate of the working oil supplied from the actuator control valve AV to the other hydraulic actuator AC1 is reduced by reducing the current value supplied from the control device U1 to the actuator control valve AV.

[0236] In addition, the reduction amount of the flow rate of the working oil supplied from the actuator control valve AV to another hydraulic actuator AC1 (the reduction amount of the pilot control pressure) can also be set according to each other hydraulic actuator AC1 (swing motor MT, boom cylinder C3, boom cylinder C4, work tool cylinder C5).

[0237] However, there has been a problem in the related art that, when another hydraulic actuator AC1 is operated during traveling, the flow rate of hydraulic oil supplied to the traveling motor M1 is sucked by the other hydraulic actuator AC1 , and the traveling speed is reduced, resulting in a seizure.

[0238] In this embodiment, when the other hydraulic actuator AC1 is operated during traveling, the flow rate of the hydraulic oil supplied from the actuator control valve AV to the other hydraulic actuator AC1 is reduced, so that the flow rate of the hydraulic oil supplied to the traveling motor M1 can be ensured, and the reduction in traveling speed can be suppressed. In addition, since the load sensing system is provided, the intermediate flow rate characteristic is stable, so even if the flow rate of the hydraulic oil is reduced by reducing the pilot control pressure to reduce the speed of the other hydraulic actuator AC1, stable operation can be performed.

[0239] In the third embodiment, even when the travel motor (second hydraulic actuator) M1 and another hydraulic actuator (first hydraulic actuator) AC1 different from the travel motor M1 are operated in combination, the actions of the travel motor M1 and the components driven by the other hydraulic actuator AC1 can be coordinated.

[0240] In addition, in the present embodiment, the first travel control valve V5 and the second travel control valve V4 are controlled by the pilot control pressure controlled by the control signal sent from the control device U1, but the present invention is not limited thereto, and the pilot operation may be performed by the pilot control pressure output from the remote control valve operated by the operating member. In addition, the first travel control valve V5 and the second travel control valve V4 may be valves directly operated by the operating member (manual operation).

[0241] In addition, in the above-mentioned hydraulic system, each control valve V1~V10 (each directional switching valve DV1~DV10) is composed of a pilot proportional solenoid valve, and the control device U1 controls the pilot control pressure by controlling the current value supplied to each control valve V1~V10, thereby controlling each control valve V1~V10, but it is not limited to this.

[0242] For example, Fig.10 As shown, it can also be constructed so that each control valve V1~V10 is composed of a pilot-operated switching valve, which is pilot-operated by a pilot control pressure acting on a pair of pilot pressure-receiving parts Va1, Va2, and is constructed to be provided with a pair of proportional solenoid valves V21, V22 controlled by the control device U1, and the pilot control pressure is supplied from the proportional solenoid valve V21 on one side to the pilot pressure-receiving part Va1 on one side, and the pilot control pressure is supplied from the proportional solenoid valve V22 on the other side to the pilot pressure-receiving part Va2 on the other side, thereby controlling the direction and flow rate of the working oil relative to the hydraulic actuators MT, ML, MR, C1~C6.

[0243] In addition, if Fig.11 As shown, each of the control valves V1 to V10 may be constituted by a proportional electromagnetic directional / flow control valve in which a spool is directly driven by a proportional solenoid so11 supplied with electric current from the control device U1.

[0244] The above-mentioned working machine 1 comprises: a machine body 2; a first hydraulic actuator C3, AC1 mounted on the machine body 2; a first control valve V2, AV for controlling the first hydraulic actuator C3, AC1; a control device U1 for controlling the first control valve V2, AV; and a second hydraulic actuator AC, M1 different from the first hydraulic actuator C3, AC1. When the second hydraulic actuator AC, M1 and the first hydraulic actuator C3, AC1 are operated in combination, the control device U1 reduces the change 53, 62, 153 of the flow rate of the working oil supplied from the first control valve V2, AV to the first hydraulic actuator C3, AC1 relative to the change in the operation amount of the first hydraulic actuator C3, AC1, compared with when the first hydraulic actuator C3, AC1 is operated alone.

[0245] According to this configuration, when the first hydraulic actuator C3, AC1 and the second hydraulic actuator AC, M1 are operated in combination, the operations of the components operated by the first hydraulic actuator C3, AC1 and the components operated by the second hydraulic actuator AC, M1 can be coordinated.

[0246] In addition, it has a boom 15 supported on the machine body 2 so as to be able to swing up and down. The first hydraulic actuator is a boom cylinder C3 that swings the boom 15 up and down. The first control valve is a boom control valve V2 that controls the boom cylinder C3. The second hydraulic actuator is another hydraulic actuator AC that is different from the boom cylinder C3.

[0247] According to this configuration, when the other hydraulic actuator AC and the boom cylinder C3 are operated in combination, the operations of the boom 15 and the components driven by the other hydraulic actuator AC can be coordinated.

[0248] The control device U1 includes a boom flow rate suppressing unit Ub which reduces the change amounts 53 and 62 by reducing the flow rate of hydraulic oil supplied from the boom control valve V2 to the boom cylinder C3 when the boom cylinder C3 is operated while the other hydraulic actuator AC is being operated.

[0249] According to this configuration, when the boom cylinder C3 is operated while another hydraulic actuator AC is being operated, the flow rate of hydraulic oil supplied from the boom control valve V2 to the boom cylinder C3 is reduced, so that the boom characteristics become smooth and the machine body 2 can be stabilized.

[0250] The boom control valve V2 is pilot operated by a pilot pressure controlled by a control signal sent from the control device U1 , and the boom flow rate suppressor Ub reduces the pilot pressure when the boom cylinder C3 is operated while other hydraulic actuators AC are being operated.

[0251] According to this configuration, the flow rate control of the boom control valve V2 can be easily performed.

[0252] The boom control valve V2 is controlled based on the current value supplied from the control device U1 , and the boom flow rate suppressor Ub reduces the current value supplied to the boom control valve V2 when the boom cylinder C3 is operated while the other hydraulic actuators AC are being operated.

[0253] This configuration also makes it possible to easily control the flow rate of the boom control valve V2.

[0254] In addition, it is provided with: a boom 16, which is connected on the front end side of the boom 15 in a manner capable of swinging in a direction approaching the boom 15, i.e., a boom loading direction D1, and a direction away from the boom 15, i.e., a boom unloading direction D2; and a boom cylinder C4, which swings the boom 16. The other hydraulic actuator AC is the boom cylinder C4. When the boom cylinder C3 is operated while the boom cylinder C4 is operated, the boom flow suppression unit Ub reduces the flow of the working oil supplied from the boom control valve V2 to the boom cylinder C3.

[0255] According to this configuration, when the boom 15 and the arm 16 are operated in combination, the boom characteristics become smooth, the machine body 2 can be stabilized, and the speed of the arm 16 can be ensured.

[0256] In addition, when the boom 15 is raised while the boom 16 is swung in the boom loading direction D1, or when the boom 15 is lowered while the boom 16 is swung in the boom unloading direction D2, the boom flow suppression unit Ub reduces the flow of the working oil supplied from the boom control valve V2 to the boom cylinder C3.

[0257] With this configuration, when the boom 15 and the arm 16 are operated in combination, the boom characteristics become smooth, the machine body 2 can be stabilized, and the speed of the arm 16 can be ensured.

[0258] In addition, there is an operating component 41 for operating the boom cylinder C3, and the control device U1 has a control unit Ua. When the boom cylinder C3 is operated alone, the control unit Ua controls the flow rate of the working oil supplied from the boom control valve V2 to the boom cylinder C3 according to the operation amount of the operating component 41. Relative to the operation amount of the operating component 41, the boom flow suppression unit Ub supplies the working oil from the boom control valve V2 to the boom cylinder C3 at a flow rate less than the flow rate of the working oil controlled by the control unit Ua according to the operation amount.

[0259] This structure can stabilize the boom characteristics and stabilize the machine body 2 .

[0260] In addition, the control device U1 has a boom flow increment unit Uc. When a combined operation is performed on other hydraulic actuators AC and the boom cylinder C3, the boom flow increment unit Uc sets a higher setting of the starting side 57 of the boom control valve V2 for the working oil flow relative to the operating amount of the boom cylinder C3 than when the boom cylinder C3 is operated alone. The greater the operating amount of the boom cylinder C3, the smaller the difference 58 between the working oil flow relative to the operating amount of the boom cylinder C3 between the case of a combined operation and the case of a single operation, thereby reducing the changes 53, 62.

[0261] According to this configuration, when the other hydraulic actuator AC and the boom cylinder C3 are operated in combination, the operation of the boom 15 and the components driven by the other hydraulic actuator AC can be coordinated.

[0262] The boom control valve V2 is pilot operated by a pilot pressure controlled by a control signal sent from the control device U1 , and when other hydraulic actuators AC and the boom cylinder C3 are compositely operated, the boom flow rate increasing unit Uc increases the pilot pressure.

[0263] According to this configuration, the flow rate control of the boom control valve V2 can be easily performed.

[0264] The boom control valve V2 is controlled based on the current value supplied from the control device U1 , and when the other hydraulic actuator AC and the boom cylinder C3 are operated in combination, the boom flow rate increasing unit Uc increases the current value supplied to the boom control valve V2 .

[0265] With this configuration, the flow rate control of the boom control valve V2 can be easily performed.

[0266] In addition, it is provided with: a boom 16, which is connected to the front end side of the boom 15 in a manner that allows it to swing in a direction approaching the boom 15, i.e., a boom loading direction D1, and a direction away from the boom 15, i.e., a boom unloading direction D2; and a boom cylinder C4, which swings the boom 16. The other hydraulic actuator AC is the boom cylinder C4. When the boom cylinder C3 is operated while the boom cylinder C4 is operated, the boom flow increment part Uc is the flow increment of the working oil supplied from the boom control valve V2 to the boom cylinder C3.

[0267] According to this configuration, when the boom 15 and the arm 16 are operated in combination, the actions of the boom 15 and the arm 16 can be coordinated.

[0268] In addition, when the boom 15 is raised while the boom 16 is swung in the boom loading direction D1, or when the boom 15 is lowered while the boom 16 is swung in the boom unloading direction D2, the boom flow increasing unit Uc increases the flow rate of the working oil supplied from the boom control valve V2 to the boom cylinder C3.

[0269] According to this configuration, for example, when the boom 15 and the arm 16 are operated in combination to perform a horizontal pulling operation, the actions of the boom 15 and the arm 16 can be coordinated.

[0270] In addition, there is an operating component 41 for operating the boom cylinder C3, and the control device U1 has a control unit Ua. When the boom cylinder C3 is operated alone, the control unit Ua controls the flow rate of the working oil supplied from the boom control valve V2 to the boom cylinder C3 according to the operation amount of the operating component 41. Relative to the operation amount of the operating component 41, the boom flow increment unit Uc supplies working oil from the boom control valve V2 to the boom cylinder C3 at a flow rate greater than the flow rate of the working oil controlled by the control unit Ua according to the operation amount.

[0271] This structure enables the actions of the boom 15 and the arm 16 to be coordinated.

[0272] Furthermore, when the boom cylinder C3 is being independently operated in the direction of raising the boom 15 , if the other hydraulic actuators AC are being operated, the control device U1 deactivates the boom flow rate increasing portion Uc.

[0273] According to this structure, for example, a stable lifting operation can be performed.

[0274] In addition, there is a travel device 3 that supports the body 2 in a travelable manner, the second hydraulic actuator is a travel motor M1 composed of a hydraulic motor that drives the travel device 3, the first hydraulic actuator is another hydraulic actuator AC1 different from the travel motor M1, the first control valve is an actuator control valve AV that controls the other hydraulic actuator AC1, and the control device U1 has an actuator flow suppression unit Ue. When the other hydraulic actuator AC1 is operated while the travel motor M1 is being driven, the actuator flow suppression unit Ue reduces the flow of working oil supplied from the actuator control valve AV to the other hydraulic actuator AC1.

[0275] According to this configuration, when the other hydraulic actuator AC1 and the travel motor M1 are operated in combination, the operation of the travel device 3 and the operation of the components driven by the other hydraulic actuator AC1 can be coordinated.

[0276] In addition, it is provided with: a variable capacity pump 21, which discharges working oil for operating multiple hydraulic actuators MT, ML, MR, C1 to C6 including a first hydraulic actuator C3, AC1 and a second hydraulic actuator AC, M1; and a load sensing system, which controls the pump 21 so that the pressure difference obtained by subtracting the highest load pressure among the multiple hydraulic actuators MT, ML, MR, C1 to C6 from the discharge pressure of the pump 21 becomes a constant pressure.

[0277] According to this configuration, since the load sensing system is provided, the intermediate flow rate characteristics are stable, and thus even if the flow rate of the hydraulic oil is reduced or increased, stable operation can be performed.

[0278] In addition, it is equipped with: a variable capacity pump 21, which discharges working oil for operating multiple hydraulic actuators MT, ML, MR, C1 to C6 including the boom cylinder C3 and other hydraulic actuators AC; and a load sensing system, which controls the pump 21 so that the pressure difference obtained by subtracting the highest load pressure among the multiple hydraulic actuators MT, ML, MR, C1 to C6 from the discharge pressure of the pump 21 becomes a constant pressure.

[0279] With this configuration, since the load sensing system is provided, the intermediate flow rate characteristics are stable, and thus stable operation can be performed even when the flow rate of the hydraulic oil is reduced or increased.

[0280] In addition, the above-mentioned working machine 1 includes: a body 2; a travel device 3, which supports the body 2 in a travelable manner; a travel motor M1 composed of a hydraulic motor that drives the travel device 3; another hydraulic actuator AC1 different from the travel motor M1; an actuator control valve AV that controls the other hydraulic actuator AC1; and a control device U1 that controls the actuator control valve AV, the control device U1 has an actuator flow suppression unit Ue, and when the other hydraulic actuator AC1 is operated while the travel device 3 is being driven, the actuator flow suppression unit Ue reduces the flow rate of the working oil supplied from the actuator control valve AV to the other hydraulic actuator AC1.

[0281] According to this structure, when another hydraulic actuator AC1 different from the travel motor M1 is operated during driving, the flow rate of the working oil supplied from the actuator control valve AV to the other hydraulic actuator AC1 can be reduced, thereby ensuring the flow rate of the working oil supplied to the travel motor M1 and suppressing the reduction in driving speed.

[0282] The actuator control valve AV is pilot operated by a pilot pressure controlled by a control signal sent from the control device U1 , and when another hydraulic actuator AC1 is operated while the travel device 3 is being driven, the actuator flow rate suppressor Ue reduces the pilot pressure.

[0283] According to this configuration, the flow rate control of the actuator control valve AV can be easily performed.

[0284] The actuator control valve AV is controlled based on the current value supplied from the control device U1 , and when another hydraulic actuator AC1 is operated while the travel device 3 is being driven, the actuator flow rate suppressor Ue reduces the current value supplied to the actuator control valve AV.

[0285] With this configuration, the flow rate control of the actuator control valve AV can be easily performed.

[0286] In addition, there is an operating component 41 for operating another hydraulic actuator AC1, and the control device U1 has a control unit Ua. When the other hydraulic actuator AC1 is operated alone, the control unit Ua controls the flow rate of the working oil supplied from the actuator control valve AV to the other hydraulic actuator AC1 according to the operation amount of the operating component 41, and relative to the operation amount of the operating component, the actuator flow suppression unit Ue supplies the working oil from the actuator control valve AV to the other hydraulic actuator AC1 at a flow rate less than the flow rate of the working oil controlled by the control unit Ua according to the operation amount.

[0287] Even with this configuration, it is possible to suppress a decrease in the traveling speed by ensuring the flow rate of the hydraulic oil supplied to the traveling motor M1 .

[0288] In addition, it is equipped with: a boom cylinder C3, which drives a boom 15 supported on the body 2 in a manner that allows it to swing up and down; a boom cylinder C4, which drives a boom 16 connected to the front end side of the boom 15; a work tool cylinder C5, which drives a work tool 17 connected to the front end side of the boom 16 in a manner that allows it to swing; and a rotary motor MT, which is a hydraulic motor that rotates the body 2 around an axis extending in the up and down direction. Another hydraulic actuator AC1 includes at least a boom cylinder C3, a boom cylinder C4, a work tool cylinder C5 and a rotary motor MT.

[0289] According to this configuration, it is possible to suppress a decrease in the travel speed when the boom 15 , the arm 16 , the working tool 17 , and the machine body 2 are operated during travel.

[0290] In addition, it is equipped with: a variable capacity pump 21, which discharges working oil that operates multiple hydraulic actuators MT, ML, MR, C1 to C6 including a travel motor M1 and another hydraulic actuator AC1; and a load sensing system, which controls the pump 21 so that the pressure difference obtained by subtracting the highest load pressure among the multiple hydraulic actuators MT, ML, MR, C1 to C6 from the discharge pressure of the pump 21 becomes a constant pressure.

[0291] According to this configuration, since the load sensing system is provided, the intermediate flow rate characteristics are stable, and thus even if the flow rate of the hydraulic oil is reduced, stable operation can be performed.

[0292] The above describes one embodiment of the present invention, but it should be considered that the embodiment disclosed this time is illustrative in all aspects and not restrictive. The scope of the present invention is not represented by the above description but by the scope of the claims, including the meaning equivalent to the scope of the claims and all changes within the scope.

[0293] Description of symbols

[0294] 2 Body

[0295] 3 Driving device

[0296] 15 Boom

[0297] 16 stick

[0298] 21 Pumps

[0299] 41 Operating parts

[0300] 57 Starting side

[0301] 58 bad

[0302] 53 Change

[0303] 62 Change

[0304] 153 Change

[0305] AC Second Hydraulic Actuator (Other Hydraulic Actuators)

[0306] AC1 first hydraulic actuator (additional hydraulic actuator)

[0307] AV first control valve

[0308] C3 first hydraulic actuator (boom cylinder)

[0309] C4 stick cylinder

[0310] D1 bucket arm shovel loading direction

[0311] D2 arm unloading direction

[0312] M1 Second hydraulic actuator (travel motor)

[0313] U1 Control Device

[0314] Ua control unit

[0315] Ub boom flow suppression unit

[0316] Uc boom flow increment unit

[0317] Ue actuator flow suppression unit

[0318] V2 first control valve (boom control valve).

Claims

1. A working machine comprising: Body; A movable arm, the movable arm is supported on the machine body so as to be able to swing up and down; a first hydraulic actuator mounted on the machine body; an operating member that operates the first hydraulic actuator; a first control valve that changes a flow rate of hydraulic oil supplied to the first hydraulic actuator; a control device for controlling the operation of the first control valve according to the operation amount of the operating member; and a second hydraulic actuator different from the first hydraulic actuator, The first hydraulic actuator is a boom cylinder that causes the boom to swing up and down. The first control valve is a boom control valve for controlling the boom, The second hydraulic actuator is another hydraulic actuator different from the boom cylinder, The control device controls the flow rate of the hydraulic oil supplied from the boom control valve to the boom cylinder by proportionally controlling the movement of the boom control valve according to the operation amount of the operation member when the boom cylinder is operated alone without driving the other hydraulic actuators. The action of the boom control valve is proportionally controlled according to the operation amount of the operating component, so that: when the other hydraulic actuators and the boom cylinder are subjected to a combined operation, as compared with when the boom cylinder is operated alone with the same operation amount as in the combined operation, the change in the flow rate of the working oil supplied from the boom control valve to the boom cylinder relative to the change in the operation amount of the operating component increases with the position of the operating component when the boom control valve starts to output the working oil.

2. The working machine according to claim 1, wherein: The control device has a boom flow suppression unit, which reduces the change amount by reducing the flow rate of the working oil supplied from the boom control valve to the boom cylinder, compared with a case where the boom cylinder is operated alone with the same operation amount as that of the composite operation by the operating component on the boom cylinder.

3. The working machine according to claim 2, wherein: The working machine comprises: an arm connected to the front end side of the boom so as to be swingable in a direction approaching the boom, that is, an arm loading direction, and a direction away from the boom, that is, an arm unloading direction; and A boom cylinder that causes the boom to swing, The other hydraulic actuator is the boom cylinder, In the case of a combined operation by operating the boom cylinder while operating the boom cylinder, the boom flow suppression unit reduces the flow rate of the working oil supplied from the boom control valve to the boom cylinder, compared to a case where the boom cylinder is operated alone with the same operation amount as in the combined operation.

4. The working machine according to claim 3, wherein: In the case of a combined operation in which the boom is raised while the boom is swung in the boom loading direction, or in the case of a combined operation in which the boom is lowered while the boom is swung in the boom unloading direction, the boom flow suppression unit reduces the flow rate of the working oil supplied from the boom control valve to the boom cylinder, compared to a case in which the boom cylinder is operated alone with the same operation amount as in the combined operation.

5. The working machine according to any one of claims 2 to 4, wherein: The control device includes a control unit that controls the flow rate of hydraulic oil supplied from the boom control valve to the boom cylinder according to the operation amount of the operation member when the boom cylinder is operated independently. The boom flow rate suppressing unit supplies hydraulic oil from the boom control valve to the boom cylinder at a flow rate smaller than a flow rate of hydraulic oil controlled by the control unit according to the operation amount of the operation member.

6. The working machine according to claim 1, wherein: The control device has a boom flow increment unit, which sets a setting of the flow rate of working oil output from the boom control valve relative to the operation amount of the operating component when the boom control valve starts to output working oil higher than when the boom cylinder is operated alone with the same operation amount as that of the combined operation, when the other hydraulic actuators and the boom cylinder are subjected to a combined operation. The boom flow increment unit proportionally controls the action of the boom control valve according to the operation amount of the operating component, thereby reducing the change amount, so that: the more the operation amount of the operating component is increased starting from the position of the operating component when the boom control valve starts to output working oil, the smaller the difference in the flow rate of working oil relative to the operation amount of the operating component between when the combined operation is performed and when the single operation is performed.

7. The working machine according to claim 6, wherein: The working machine comprises: an arm connected to the front end side of the boom so as to be swingable in a direction approaching the boom, that is, an arm loading direction, and a direction away from the boom, that is, an arm unloading direction; and A boom cylinder that causes the boom to swing, The other hydraulic actuator is the boom cylinder, In the case of a combined operation of operating the boom cylinder while operating the boom cylinder at the same time, the boom flow increment unit increases the flow of the working oil supplied from the boom control valve to the boom cylinder, compared to a case where the boom cylinder is operated alone with the same operation amount as in the combined operation, so that the amount of change becomes smaller as the position of the operating part when the working oil starts to be output from the boom control valve increases and the operation amount of the operating part increases.

8. The working machine according to claim 7, wherein: In the case of a combined operation in which the boom is raised while the boom is swung in the boom loading direction, or in the case of a combined operation in which the boom is lowered while the boom is swung in the boom unloading direction, the boom flow increment unit increases the flow rate of the working oil supplied from the boom control valve to the boom cylinder, compared to a case in which the boom cylinder is operated alone with the same operation amount as in the combined operation, so that the amount of change becomes smaller as the position of the operating component when the working oil starts to be output from the boom control valve increases.

9. The working machine according to any one of claims 6 to 8, wherein: The control device includes a control unit that controls the flow rate of hydraulic oil supplied from the boom control valve to the boom cylinder according to the operation amount of the operation member when the boom cylinder is operated independently. Relative to the operation amount of the operating component, the boom flow increment unit supplies working oil at a flow rate greater than the flow rate of the working oil controlled by the control unit according to the operation amount from the boom control valve to the boom cylinder, so that the more the position of the operating component when the working oil starts to be output from the boom control valve increases, the smaller the change becomes.

10. The working machine according to claim 6, wherein: The control device deactivates the boom flow rate increasing section when the other hydraulic actuator is operated while the boom cylinder is being operated alone in a direction to raise the boom.

11. A working machine comprising: Body; A travel device for supporting the machine body in a travelable manner; a first hydraulic actuator mounted on the machine body; an operating member that operates the first hydraulic actuator; a first control valve that changes a flow rate of hydraulic oil supplied to the first hydraulic actuator; a control device for controlling the operation of the first control valve according to the operation amount of the operating member; and a second hydraulic actuator different from the first hydraulic actuator, The second hydraulic actuator is a travel motor consisting of a hydraulic motor driving the travel device. The first hydraulic actuator is a hydraulic actuator different from the travel motor, the first control valve is an actuator control valve controlling the further hydraulic actuator, The actuator control valve is a pilot-operated proportional solenoid valve that is pilot-operated by a pilot control pressure controlled by a control signal sent from the control device. The control device outputs a control signal for proportionally controlling the operation of the actuator control valve according to the operation amount of the operating member to the actuator control valve when the other hydraulic actuator is independently operated without driving the travel motor, thereby controlling the flow rate of the working oil supplied from the boom control valve to the other hydraulic actuator. When the other hydraulic actuator is operated while the travel motor is being driven, the flow rate of the working oil supplied from the actuator control valve to the other hydraulic actuator is reduced compared to the flow rate of the working oil supplied to the other hydraulic actuator when the other hydraulic actuator is operated alone with the same operation amount, and a control signal for proportionally controlling the action of the actuator control valve according to the operation amount of the operating component is output to the actuator control valve, and the reduced flow rate of the working oil is set for each of the other hydraulic actuators.

12. A working machine comprising: Body; A travel device for supporting the machine body in a travelable manner; a first hydraulic actuator mounted on the machine body; an operating member that operates the first hydraulic actuator; a first control valve that changes a flow rate of hydraulic oil supplied to the first hydraulic actuator; a control device for controlling the operation of the first control valve according to the operation amount of the operating member; and a second hydraulic actuator different from the first hydraulic actuator, The second hydraulic actuator is a travel motor consisting of a hydraulic motor driving the travel device. The first hydraulic actuator is a hydraulic actuator different from the travel motor, the first control valve is an actuator control valve controlling the further hydraulic actuator, The actuator control valve is controlled according to the current value supplied by the control device, The control device controls the flow rate of the working oil supplied from the actuator control valve to the other hydraulic actuator by supplying a current value for proportionally controlling the operation of the actuator control valve according to the operation amount of the operating member to the actuator control valve when the other hydraulic actuator is independently operated without driving the travel motor. When the other hydraulic actuator is operated while the travel motor is being driven, the flow rate of the working oil supplied from the actuator control valve to the other hydraulic actuator is reduced compared to the flow rate of the working oil supplied to the other hydraulic actuator when the other hydraulic actuator is operated alone with the same operation amount, and a current value for proportionally controlling the action of the actuator control valve according to the operation amount of the operating component is output to the actuator control valve, and the reduced flow rate of the working oil is set for each of the other hydraulic actuators.

13. The working machine according to claim 11 or 12, wherein: The control device includes a control unit that controls a flow rate of hydraulic oil supplied from the actuator control valve to the other hydraulic actuator according to an operation amount of the operating member when the other hydraulic actuator is operated independently. Furthermore, the control device includes an actuator flow suppressing unit that supplies hydraulic oil from the actuator control valve to the other hydraulic actuator at a flow rate less than a flow rate of hydraulic oil controlled by the control unit according to the operation amount relative to the operation amount of the operating member.

14. The working machine according to claim 11 or 12, wherein: The working machine comprises: A boom cylinder that drives a boom supported on the machine body in a manner that allows it to swing up and down; an arm cylinder that drives an arm swingably connected to a front end of the boom; a working tool cylinder that drives a working tool connected to the front end side of the arm; and a rotary motor, which is a hydraulic motor that rotates the machine body around an axis extending in the vertical direction, The other hydraulic actuator includes at least the boom cylinder, the arm cylinder, the work tool cylinder, and the swing motor.

15. The working machine according to any one of claims 1, 11 and 12, wherein: The working machine comprises: a variable displacement pump that discharges hydraulic oil for operating a plurality of hydraulic actuators including the first hydraulic actuator and the second hydraulic actuator; and The load sensing system controls the pump so that a differential pressure obtained by subtracting a highest load pressure among the plurality of hydraulic actuators from a discharge pressure of the pump becomes a constant pressure.

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