Independent control hydraulic system of large loader

Abstract

The invention relates to the technical field of loaders, in particular to an independent control hydraulic system of a large loader. Comprising a first working pump and a second working pump; a P1 port of the first working valve is connected with the second working pump, and a P2 port of the first working valve is connected with the first working pump; a first flow collecting valve is arranged between the P1 port and the P2 port of the first working valve; the first working valve comprises a first movable arm working unit and a first tipping bucket working unit; the flow of the first working pump and the flow of the second working pump can be converged in the first working valve through the first converging valve to be used by the same working unit, so that the requirements for large flow and high speed of a movable arm oil cylinder or a tipping bucket oil cylinder are met, and meanwhile, the combined action of a movable arm and a tipping bucket can be achieved through different working units. Different flow requirements of different working units are met, the working pump and the executing mechanism are independently controlled, and each working unit can obtain stable flow supply.

Description

Technical Field

[0001] The present invention relates to the technical field of loaders, and in particular to an independently controlled hydraulic system for a large loader. Background Art

[0002] The loader hydraulic system mainly includes the steering system and the working system. The steering pump is mainly responsible for supplying oil to the steering cylinder through the steering control valve to control the vehicle steering. The working pump is mainly responsible for supplying oil to the boom and bucket cylinder through the working control valve to control the shoveling operation of the working device.

[0003] To meet the high flow requirements of ultra-large loaders, the working system is often equipped with multiple working pumps and multiple working valves. The working pumps are often dual-pump, where the flow is combined before supplying the working valve. This creates strong coupling between the pumps and relies on the travel limits of each working valve to distribute flow, increasing throttling losses and significant energy loss. Some products use series-parallel working valves, relying on the valve core shoulder to control the oil circuit. This prioritizes flow distribution to the working valve closest to the oil inlet, while the distant working valve receives little or no flow. This limits flow distribution capabilities and results in high system throttling losses. Summary of the Invention

[0004] The purpose of the present invention is to provide an independently controlled hydraulic system for a large loader, wherein the flow of the first working pump and the second working pump can be combined in the first working valve through the first combining valve for use in the same working link (the first boom working link or the first bucket working link) to meet the large flow and high speed requirements of the boom cylinder or the bucket cylinder. At the same time, it can also be supplied to different working links (the first working pump supplies the first bucket working link, and the second working pump supplies the first boom working link) to realize the combined action of the boom and the bucket, and meet the different flow requirements of different working links. The working pumps (the first working pump and the second working pump) and the actuators (the boom cylinder and the bucket cylinder) are independently controlled, and each working link (the first boom working link and the first bucket working link) can obtain a stable flow supply.

[0005] In order to achieve the above object, the present invention adopts the following technical solutions: In a first aspect, the present invention provides an independent control hydraulic system for a large loader, comprising: a first working pump and a second working pump; A first working valve, with port P1 connected to the second working pump and port P2 connected to the first working pump; a first converging valve is provided between ports P1 and P2 of the first working valve; the first working valve includes a first boom working link and a first bucket working link; When the first merging valve is open and the first boom working joint is in the working position, the flow of the first working pump can merge with the second working pump at the P1 port and supply oil to the boom cylinder through the first boom working joint; When the first merging valve is open and the first dump bucket working link is in the working position, the flow of the second working pump can merge with the first working pump at the P2 port and supply oil to the dump bucket cylinder through the first dump bucket working link; When the first combining valve is closed and the first boom working link and the first bucket working link are both in the working position, the first working pump supplies oil to the bucket cylinder through the first bucket working link, and the second working pump supplies oil to the boom cylinder through the first boom working link.

[0006] Optionally, the first movable arm working joint has a left working position, a first right working position and a second right working position; When the first boom working link is in the left working position, the hydraulic oil at the P1 port can pass through the first one-way valve, the first boom working link, the first load holding valve, and the Ab1 port of the first working valve to reach the rodless chamber of the boom cylinder; When the first boom working link is in the right first working position, the hydraulic oil at the P1 port can pass through the first one-way valve, the first boom working link, and the Bb1 port of the first working valve to reach the rod chamber of the boom cylinder; When the first boom working link is in the second right working position, the rodless chamber of the boom cylinder is connected to the return oil port of the first boom working link through the Ab1 port of the first working valve, and the rod chamber of the boom cylinder is connected to the return oil port of the first boom working link through the Bb1 port of the first working valve. At this time, if the first bucket working link is in the working position, when the first merging valve is opened, the first working pump and the second working pump can merge to supply oil to the bucket cylinder through the first bucket working link. When the first merging valve is closed, the first working pump can supply oil to the bucket cylinder through the first bucket working link.

[0007] Optionally, it also includes: The second proportional solenoid valve and the third proportional solenoid valve are respectively connected to the left end and the right end of the first boom working link to control the first boom working link to switch between the left working position, the first right working position and the second right working position.

[0008] Optionally, the first dump bucket working link has a left working position and a right working position; When the first bucket working link is in the left working position, the hydraulic oil at the P2 port can pass through the second one-way valve, the first bucket working link and the Ac1 port of the first working valve to reach the rodless chamber of the bucket cylinder; When the first bucket working link is in the right working position, the hydraulic oil at the P2 port can reach the rod chamber of the bucket cylinder through the second one-way valve, the first bucket working link and the Bc1 port of the first working valve.

[0009] Optionally, it also includes: The first proportional solenoid valve and the fourth proportional solenoid valve are respectively connected to the left end and the right end of the first dump bucket working link to control the first dump bucket working link to switch between the left working position and the right working position.

[0010] Optionally, it also includes: The third working pump and the fourth working pump, The second working valve has a P3 port connected to the third working pump and a P4 port connected to the fourth working pump. A second combining valve is provided between the P3 and P4 ports of the second working valve. The second working valve includes a second boom working link and a second bucket working link. When the first merging valve and the second merging valve are both open and the first boom working link and the second boom working link are both in the working position, the flow of the fourth working pump can merge with the third working pump at the P3 port and pass through the second boom working link to cooperate with the first working pump and the second working pump to supply oil to the boom cylinder; When the first merging valve and the second merging valve are both open and the first and second dump bucket working links are both in the working position, the flow of the third working pump can merge with the fourth working pump at the P4 port and pass through the second dump bucket working link to cooperate with the first and second working pumps to supply oil to the dump bucket cylinder; When the second combining valve is closed and the first boom working link and the first bucket working link are both in the working position, the third working pump can supply oil to the boom cylinder through the second boom working link, and the fourth working pump can supply oil to the bucket cylinder through the second bucket working link.

[0011] Optionally, the second movable arm working joint has a left working position, a first right working position and a second right working position; When the second boom working link is in the left working position, the hydraulic oil at the P3 port can pass through the third one-way valve, the second boom working link, the second load holding valve, and the Ab2 port of the second working valve to reach the rodless chamber of the boom cylinder; When the second boom working joint is in the right first working position, the hydraulic oil at the P3 port can pass through the third one-way valve, the second boom working joint, and the Bb2 port of the second working valve to reach the rod chamber of the boom cylinder; When the second boom working link is in the second right working position, the rodless chamber of the boom cylinder is connected to the return oil port of the second boom working link through the Ab2 port of the second working valve, and the rod chamber of the boom cylinder is connected to the return oil port of the first boom working link through the Bb2 port of the second working valve. At this time, if the second bucket working link is in the working position, when the second merging valve is opened, the third working pump and the fourth working pump can merge to supply oil to the bucket cylinder through the first bucket working link. When the second merging valve is closed, the fourth working pump can supply oil to the bucket cylinder through the second bucket working link.

[0012] Optionally, the second dump working link has a left working position and a right working position; When the second bucket working link is in the left working position, the hydraulic oil at the P4 port can pass through the fourth one-way valve, the second bucket working link and the Ac2 port of the second working valve to reach the rodless chamber of the bucket cylinder; When the second bucket working link is in the right working position, the hydraulic oil at the P4 port can reach the rod chamber of the bucket cylinder through the fourth one-way valve, the second bucket working link and the Bc2 port of the second working valve.

[0013] Optionally, it also includes: a sixth proportional solenoid valve and a seventh proportional solenoid valve, connected to the left end and the right end of the second boom working link, respectively, to control the second boom working link to switch between the left working position, the first right working position, and the second right working position; a fifth proportional solenoid valve and an eighth proportional solenoid valve, connected to the left end and the right end of the second dump bucket working link, respectively, to control the second dump bucket working link to switch between the left working position and the right working position; The first merging proportional solenoid valve and the second merging proportional solenoid valve are respectively connected to the first merging valve and the second merging valve to control the valve port opening.

[0014] Optionally, it also includes: Steering pump, connected to the steering cylinder through the steering control valve; A controller is connected to a steering operating mechanism, a power unit and an electric control handle; the steering operating mechanism is used to control the steering pump to drive the steering cylinder; the power unit is used to drive the first working pump, the second working pump, the third working pump and the fourth working pump; the electric control handle is used to control the first working valve and the second working valve to enable the boom cylinder and the bucket cylinder to perform specified actions.

[0015] Compared with the prior art, the present invention has the following beneficial effects: 1. The present invention uses a first combining valve to allow the flow of the first working pump and the second working pump to be combined in the first working valve for use in the same working link (the first boom working link or the first bucket working link) to meet the large flow and high speed requirements of the boom cylinder or the bucket cylinder. At the same time, it can also be supplied to different working links separately (the first working pump supplies the first bucket working link, and the second working pump supplies the first boom working link) to achieve a combined action of the boom and the bucket, meeting the different flow requirements of different working links. The working pumps (the first working pump and the second working pump) and the actuators (boom cylinder and bucket cylinder) are independently controlled, and each working link (the first boom working link and the first bucket working link) can obtain a stable flow supply.

[0016] 2. The steering system and the working system in the present invention are independent of each other and are controlled separately by the controller, which can avoid the steering failure problem caused by uneven load when the steering and working device are in combined action. Each working valve is supplied with oil by two working pumps, and each working link is individually controlled by an independent proportional solenoid valve. The oil of each two working pumps enters the same working valve respectively. The working valve is provided with a converging valve. The flow of the two pumps can be combined in the valve to supply the same working link to meet the large flow and high speed requirements of the actuator. At the same time, it can also be supplied to different working links separately to meet the different flow requirements of different working links in the same valve group. Each working pump and actuator is independently controlled.

[0017] 3. In the present invention, working links of different actuators are arranged on the same working valve, and the same actuator is controlled by multiple working links and distributed on different working valves (the bucket cylinder is controlled by the first bucket working link of the first working valve and the second bucket working link of the second working valve, and the same applies to the boom cylinder), so that multiple working links of the same actuator can be independently controlled, decoupling between the working links is achieved, and the oil inlet and return are controlled separately, which ensures the speed of the actuator while facilitating the adjustment of back pressure, reducing throttling losses, and improving movement smoothness. In addition, when compound actions can be realized, a part of the working pumps can control the working links of the same actuator through multiple working valves to control the actuator (the first working pump controls the bucket cylinder through the first bucket working link of the first working valve and the fourth working pump controls the second bucket working link of the second working valve at the same time, and the same applies to the boom cylinder; the first working pump and the second working pump can also supply oil to the boom cylinder through the first boom working link of the first working valve (similarly, the third working pump and the fourth working pump can also supply oil to the bucket cylinder through the second bucket working link of the second working valve), and at the same time, the third working pump supplies oil to the boom cylinder through the second boom working link of the second working valve, and the fourth working pump supplies oil to the bucket cylinder through the second bucket working link of the second working valve, so that a total of three working pumps supply oil to the boom cylinder and one working pump supplies oil to the bucket cylinder. Similarly, three working pumps can also supply oil to the bucket cylinder and one working pump can supply oil to the boom cylinder), and the remaining working pumps control another actuator, and each action of the actuator is independently controlled, which effectively improves the coordination of the actions, reduces the complexity of control, and shortens the debugging cycle of the entire machine. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 This is a hydraulic principle diagram of the independent control hydraulic system of the large loader in Example 1; Figure 2 for Figure 1 Hydraulic principle diagram of the first working valve in.

[0019] Figure 3 for Figure 1 Hydraulic principle diagram of the second working valve in.

[0020] Reference numerals in the figure: 1, first working pump; 2, second working pump; 3, third working pump; 4, fourth working pump; 5, pilot pump; 6, first working valve; 7, second working valve; 8, boom cylinder; 9, bucket cylinder; 10, pilot safety valve; 11, fuel tank; 12, steering pump; 13, steering control valve; 14, steering cylinder; 15, controller; 16, steering operating mechanism; 17, electric control handle; 6.1, first boom working joint; 6.2, first bucket working joint; 6.3, first converging valve; 6.4, first relief valve; 6.5, first check valve; 6.6, first port relief valve; 6.7, first oil supply valve; 6.8, second relief valve; 6.9, second check valve; 6.10, first proportional solenoid valve; 6.11, first converging proportional solenoid valve; 6.12, first load holding valve; 6.13, second proportional solenoid valve; 6.14, third proportional solenoid valve; 6.15, fourth proportional solenoid valve; 7.1, second boom working joint; 7.2, second bucket working joint; 7.3, second merging valve; 7.4, third relief valve; 7.5, third non-return valve; 7.6, second port relief valve; 7.7, second oil supply valve; 7.8, fourth relief valve; 7.9, fourth non-return valve; 7.10, fifth proportional solenoid valve; 7.11, second merging proportional solenoid valve; 7.12, second load holding valve; 7.13, sixth proportional solenoid valve; 7.14, seventh proportional solenoid valve; 7.15, eighth proportional solenoid valve. DETAILED DESCRIPTION

[0021] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, features defined as "first", "second", etc. may explicitly or implicitly include one or more of the features. In the description of the present invention, unless otherwise specified, "multiple" means two or more. In the description of the present invention, it should be noted that, unless otherwise expressly specified or limited, the terms "mounted," "connected," and "connected" should be understood in a broad sense. For example, they may refer to fixed connections, detachable connections, or integral connections; mechanical connections or electrical connections; direct connections or indirect connections through an intermediate medium; and internal communication between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on specific circumstances.

[0022] The present invention will be further described below in conjunction with the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solutions of the present invention and are not intended to limit the scope of protection of the present invention. Example 1

[0023] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below with reference to the accompanying drawings and embodiments.

[0024] Combine Figure 1 This embodiment provides an independently controlled hydraulic system for a large loader. The system includes a controller 15, a steering mechanism 16, an electric control handle 17, a power unit 18, a steering system, and a working system. The steering system and working system are independent of each other. The steering system includes a steering pump 12, a steering control valve 13, a steering cylinder 14, and the like. The working system includes a first working pump 1, a second working pump 2, a third working pump 3, and a fourth working pump 4, a pilot pump 5, a pilot safety valve 10, a first working valve 6, a second working valve 7, a boom cylinder 8, a bucket cylinder 9, and a fuel tank 11.

[0025] The electric control handle 17, power unit 18, first working valve 6, second working valve 7, steering control valve 13, steering pump 12, first working pump 1, second working pump 2, third working pump 3, and fourth working pump 4 are electrically connected to the controller 15. The controller controls the power unit 18 via electrical signals, which in turn drives the first, second, third, and fourth working pumps 1, 2, 3, 4, pilot pump 5, and steering pump 12, providing them with power. The steering operating mechanism 16 transmits a steering signal to the controller 15, which converts it into an electrical current signal and transmits it to the steering control valve 13 and steering pump 12. The steering pump 12 adjusts to an appropriate displacement and outputs a corresponding flow rate. The steering control valve 13 opens to the appropriate degree, and the oil discharged from the steering pump 12 reaches the steering cylinder 14 through the steering control valve 13, thereby causing the loader to steer. The electric control handle 17 transmits the angle signal to the controller 15, and the controller 15 converts it into an electrical signal and sends it to the first working valve 6 and the second working valve 7 and the first working pump 1, the second working pump 2, the third working pump 3 and the fourth working pump 4, so that the first working pump 1, the second working pump 2, the third working pump 3 and the fourth working pump 4 are adjusted to a suitable displacement and output a corresponding flow rate, and each working link of the first working valve 6 and the second working valve 7 opens a corresponding opening, so that the oil output by the first working pump 1, the second working pump 2, the third working pump 3 and the fourth working pump 4 reaches the boom cylinder 8 and the bucket cylinder 9, completing the action of the working device.

[0026] The first working valve 6 includes two oil inlets P1 and P2, a first boom working joint 6.1, a first bucket working joint 6.2, a first merging valve 6.3, a first relief valve 6.4, a first non-return valve 6.5, a first port relief valve 6.6, a first oil replenishment valve 6.7, a second relief valve 6.8, a second non-return valve 6.9, a first proportional solenoid valve 6.10, a first merging proportional solenoid valve 6.11, a first load holding valve 6.12, a second proportional solenoid valve 6.13, a third proportional solenoid valve 6.14, and a fourth proportional solenoid valve 6.15. The second working valve 7 includes dual oil inlets P3 and P4, a second boom working joint 7.1, a second bucket working joint 7.2, a second merging valve 7.3, a third relief valve 7.4, a third non-return valve 7.5, a second port relief valve 7.6, a second oil replenishment valve 7.7, a fourth relief valve 7.8, a fourth non-return valve 7.9, a fifth proportional solenoid valve 7.10, a second merging proportional solenoid valve 7.11, a second load holding valve 7.12, a sixth proportional solenoid valve 7.13, a seventh proportional solenoid valve 7.14, and an eighth proportional solenoid valve 7.15.

[0027] The first and second working pumps 1 and 2 supply pressurized oil to the first working valve 6 through oil inlets P2 and P1, respectively. The third and fourth working pumps 3 and 4 supply pressurized oil to the second working valve 7 through oil inlets P3 and P4, respectively. The flow direction of the oil in the main oil circuit is controlled by the different working positions of each working link on the first and second working valves 6 and 7. The oil of the same working device is controlled to merge after the working valves and enter the large or small chamber of the boom cylinder 8 and the bucket cylinder 9, causing the cylinders to extend or retract.

[0028] Pilot pump 5 supplies pilot oil to the first working valve 6 and the second working valve 7 through ports Pf1 and Pf2, respectively. The pilot oil flows through the first proportional solenoid valve 6.10, the second proportional solenoid valve 6.13, the third proportional solenoid valve 6.14, the fourth proportional solenoid valve 6.15, the fifth proportional solenoid valve 7.10, the sixth proportional solenoid valve 7.13, the seventh proportional solenoid valve 7.14, and the eighth proportional solenoid valve 7.15, acting on the end faces of the working joints to control the switching motion of the working joints, thereby controlling the boom cylinder 8 and the bucket cylinder 9 to complete their corresponding movements. The pilot oil flows through the first merging proportional solenoid valve 6.11 and the second merging proportional solenoid valve 7.11, respectively, acting on the end faces of the first merging valve 6.3 and the second merging valve 7.3 to control the switching motion of the first merging valve 6.3 and the second merging valve 7.3, thereby controlling whether the oil flows into and out of the oil inlets P1 and P2 of the first working valve 6 and the oil inlets P3 and P4 of the second working valve 7. The pilot pump 5 supplies oil to the first load holding valve 6.12 and the second load holding valve 7.12 respectively to control opening and closing.

[0029] Figure 2The diagram shows the hydraulic principle of the first working valve 6. This working valve is equipped with a first boom working link 6.1, a first dump bucket working link 6.2, a first combining valve 6.3, a first relief valve 6.4, a second relief valve 6.8, a first check valve 6.5, a second check valve 6.9, a first proportional solenoid valve 6.10, a second proportional solenoid valve 6.13, a third proportional solenoid valve 6.14, a fourth proportional solenoid valve 6.15, a first combining proportional solenoid valve 6.11, a first load-holding valve 6.12, a first port relief valve 6.6, and a first oil replenishment valve 6.7. The first working valve 6 also has oil inlets P1 and P2, an oil return port T1, a pilot oil inlet Pf1, a pilot oil return port Dr1, and working oil ports Abl, Bb1, Ac1, and Bc1. The P1 oil port is connected to the oil return port T1 through the first boom working link 6.1 and the first bucket working link 6.2. It is also connected to the first boom working link 6.1 through the first check valve 6.5. The P1 oil inlet is further connected to the oil inlet P2 through the first combining valve 6.3. The P2 oil inlet is connected to the oil return port T1 through the first bucket working link 6.2 and the first boom working link 6.1. It is also connected to the first bucket working link 6.2 through the second check valve 6.9. Oil from pilot port Pf1 acts on the first boom working link 6.1 and the first bucket working link 6.2 via the first proportional solenoid valve 6.10, the second proportional solenoid valve 6.13, the third proportional solenoid valve 6.14, and the fourth proportional solenoid valve 6.15, respectively. The pilot oil pressure differential at these two ends controls the switching action of the first boom working link 6.1 and the first bucket working link 6.2. Oil from pilot port Pf1 acts on the end face of the first converging proportional solenoid valve 6.11, controlling the switching action of the first converging valve 6.3 and, in turn, the connection between ports P1 and P2.

[0030] Figure 3The diagram shows the hydraulic principle of the second working valve 7. This hydraulic valve is equipped with a second boom working link 7.1, a second dump bucket working link 7.2, a second combining valve 7.3, a third relief valve 7.4, a fourth relief valve 7.8, a third check valve 7.5, a fourth check valve 7.9, a fifth proportional solenoid valve 7.10, a sixth proportional solenoid valve 7.13, a seventh proportional solenoid valve 7.14, an eighth proportional solenoid valve 7.15, a second combining proportional solenoid valve 7.11, a second load holding valve 7.12, a second port relief valve 7.6, and a second oil replenishment valve 7.7. The second working valve 7 also has oil inlets P3 and P4, an oil return port T2, a pilot oil inlet Pf2, a pilot oil return port Dr2, and working oil ports Ab2, Bb2, Ac2, and Bc2. The P3 oil port is connected to the oil return port T2 via the second boom working joint 7.1 and the second bucket working joint 7.2. The P3 oil inlet is also connected to the second boom working joint 7.1 via the third check valve 7.5. The P3 oil inlet is further connected to the oil inlet P4 via the second combining valve 7.3. The P4 oil inlet is connected to the oil return port T2 via the second bucket working joint 7.2 and the second boom working joint 7.1. The P4 oil inlet is also connected to the second bucket working joint 7.2 via the fourth check valve 7.9. Oil from pilot oil inlet Pf2 acts on the second boom working link 7.1 and the second bucket working link 7.2 via the fifth, sixth, seventh, and eighth proportional solenoid valves 7.10, 7.13, 7.14, and 7.15, respectively. This pressure differential between the pilot oil terminals controls the direction of these two links. Oil from pilot oil port Pf2 acts on the end faces of the second combining valve 7.3 via the second combining proportional solenoid valve 7.11, controlling the direction of this valve and, in turn, the connection between ports P3 and P4.

[0031] The working oil port Ab1 of the first working valve 6 and the working oil port Ab2 of the second working valve 7 are merged and connected to the large chamber of the boom cylinder 8, and the working oil port Bb1 of the first working valve 6 and the working oil port Bb2 of the second working valve 7 are merged and connected to the small chamber of the boom cylinder 8; the working oil port Ac1 of the first working valve 6 and the working oil port Ac2 of the second working valve 7 are merged and connected to the large chamber of the bucket cylinder 9, and the working oil port Bc1 of the first working valve 6 and the working oil port Bc2 of the second working valve 7 are merged and connected to the small chamber of the bucket cylinder 9.

[0032] Further explanation in conjunction with the work process: No steering action: The steering operating mechanism 16 does not move, the steering control valve 13 and the steering cylinder 14 do not move, and the controller 15 sends the minimum current value to the steering pump 12, making it work at the minimum displacement, discharging a small amount of flow through the steering control valve 13 back to the oil tank 11, and maintaining a standby state.

[0033] Steering action: The steering operating mechanism 16 transmits the steering signal to the controller 15, which converts it into an electrical signal and sends it to the steering pump 12 and the steering control valve 13. The steering pump 12 is adjusted to an appropriate displacement and outputs a corresponding flow rate. The steering control valve 13 opens to a corresponding degree. The oil discharged by the steering pump 12 reaches the steering cylinder 14 through the steering control valve 13, thereby causing the loader to steer.

[0034] Working device does not move: The electric control handle 17 does not move, and the controller 15 sends the minimum current value to the first working pump 1, the second working pump 2, the third working pump 3 and the fourth working pump 4. The first working pump 1, the second working pump 2, the third working pump 3 and the fourth working pump 4 operate at the minimum displacement, and each proportional solenoid valve has no current. The first working valve 6 and the second working valve 7 operate in the middle position. A small amount of oil from the second working pump 2 returns to the oil tank 11 through the oil inlet P1 of the first working valve 6, the first boom working joint 6.1, the first bucket working joint 6.2, and the return oil port T1; a small amount of oil from the first working pump 1 returns to the oil tank 11 through the oil inlet P2 of the first working valve 6, the first bucket working joint 6.2, the first boom working joint 6.1, and the return oil port T1; a small amount of oil from the third working pump 3 returns to the oil tank 11 through the oil inlet P3 of the second working valve 7, the second boom working joint 7.1, the second bucket working joint 7.2, and the return oil port T2; a small amount of oil from the fourth working pump 4 returns to the oil tank 11 through the oil inlet P4 of the second working valve 7, the second bucket working joint 7.2, the second boom working joint 7.1, and the return oil port T2.

[0035] The first merging valve 6.3 and the second merging valve 7.3 are two-position, two-way proportional directional valves. When not in operation, there is no current flowing through the first merging proportional solenoid valve 6.11 and the second merging proportional solenoid valve 7.11. The first merging valve 6.3 and the second merging valve 7.3 are in the disconnected state, and the first working pump 1, the second working pump 2, the third working pump 3 and the fourth working pump 4 return oil respectively.

[0036] Working device single action: Boom lift: When electric control handle 17 is actuated, it sends an angle signal to controller 15. Controller 15 converts this signal into a current and sends it to the first, second, third, and fourth working pumps 1, 2, 3, and 4. It also sends electrical signals to the third and seventh proportional solenoid valves 6.14, 7.14, and the first and second merging proportional solenoid valves 6.11. Oil from the Pf1 pilot inlet flows through the second proportional solenoid valve 6.13 and acts on the left end of the first boom working link 6.1. This energizes the third proportional solenoid valve 6.14, reducing the pressure in the Pf1 pilot inlet before acting on the right end of the first boom working link 6.1. The pressure differential across the first boom working link 6.1 causes the first boom working link 6.1 to shift to the left working position. When the first merging proportional solenoid valve 6.11 is energized, the oil from the P2 inlet merges with the oil from the P1 inlet through the first merging valve 6.3. The oil then flows through the first check valve 6.5, the first boom working link 6.1, and the first load-holding valve 6.12 to reach the working port Ab1. The oil from the Pf2 pilot inlet is applied to the left end of the second boom working link 7.1 via the sixth proportional solenoid valve 7.13. When the seventh proportional solenoid valve 7.14 is energized, the oil from the Pf2 pilot inlet is reduced in pressure by the seventh proportional solenoid valve 7.14 and applied to the right end of the second boom working link 7.1. The pressure differential across the second boom working link 7.1 causes the second boom working link 7.1 to shift to the left working position. When the second merging proportional solenoid valve 7.11 is energized, the oil from the P4 inlet merges with the P3 inlet through the second merging valve 7.3. The oil then flows through the second check valve 7.5, the second boom working link 7.1, and the second load-holding valve 7.12 to reach the working port Ab2. The oil from the working oil ports Ab1 and Ab2 merges and enters the large chamber of the boom cylinder 8. The oil from the small chamber of the boom cylinder 8 reaches the first boom working link 6.1 and the second boom working link 7.1 through the working oil ports Bb1 and Bb2 respectively, and then returns to the oil tank 11, thereby realizing the extension of the boom cylinder 8 and completing the boom lifting action.

[0037] During this process, the first and second merging proportional solenoid valves 6.11 and 7.11 are energized and reversed. The oil at the pilot oil inlet Pf1 passes through the first and second merging proportional solenoid valves 6.11 and 7.11 and acts on the first and second merging valves 6.3 and 7.3 respectively, so that the first and second merging valves 6.3 and 7.3 adjust their openings in proportion to the current value. An appropriate amount of oil at the oil inlet P2 merges with the oil at the oil inlet P1, and an appropriate amount of oil at the oil inlet P4 merges with the oil at the oil inlet P3, and all of them enter the second boom working link 7.1 and are jointly supplied to the boom cylinder 8.

[0038] Through this approach, four working pumps—the first, second, third, and fourth working pumps, respectively—can simultaneously supply oil to the boom cylinder 8, ensuring the extremely high flow rate required during a single boom lift, enabling rapid operation. Furthermore, the four working pumps are independent and their flow rates can be adjusted individually. The first and second merging proportional solenoid valves 6.11 and 7.11 are also independent, allowing the openings of the first and second merging proportional solenoid valves 6.3 and 7.3 to be adjusted independently, allowing the flow rates of the four working pumps to merge. Simultaneously, the second, third, sixth, and seventh proportional solenoid valves 6.13, 6.14, 7.13, and 7.14 can be individually adjusted to control the switching displacement and opening of the first and second boom working links 6.1 and 7.1, respectively. This ensures optimal flow and working link openings, matching the desired speed of the boom cylinder 8.

[0039] Boom lowering and floating lowering: Similarly, the electric control handle 17 is actuated, sending an angle signal to the controller 15. The controller 15 converts the angle signal into an electric current signal and sends it to the first working pump 1, the second working pump 2, the third working pump 3 and the fourth working pump 4. The controller also sends an electric signal to the second proportional solenoid valve 6.13 and the sixth proportional solenoid valve 7.13, the first converging proportional solenoid valve 6.11 and the second converging proportional solenoid valve 7.11. The second proportional solenoid valve 6.13 and the sixth proportional solenoid valve 7.13 obtain the first current value, the first boom working link 6.1 and the second boom working link 7.1 work in the first right working position, the flow of the first working pump 1 and the second working pump 2 merges in the first working valve 6 through the first converging valve 6.3, and then reaches the working oil port Bb1 through the first right working position of the first boom working link 6.1. At the same time, the flow of the third working pump 3 and the fourth working pump 4 merges in the second working valve 7 through the second converging valve 7.3. The oil flows through the right working position of the second boom working link 7.1 and reaches the working oil port Bb2. The flows of the working oil ports Bb1 and Bb2 merge and enter the small chamber of the boom cylinder 8. The oil in the large chamber of the boom cylinder 8 returns to the oil tank through the working oil ports Ab1 / Ab2, the opened first load holding valve 6.12 / second load holding valve 7.12, the first boom working link 6.1 / second boom working link 7.1 and the return oil ports T1 / T2, thereby retracting the boom cylinder 8 and completing the boom lowering action. Since this process is a negative load, under the action of the deadweight of the actuators such as the boom, the falling speed is fast and the required flow is small. Therefore, the controller 15 can independently adjust the displacement of the first working pump 1, the second working pump 2, the third working pump 3 and the fourth working pump 4, so that they all work at a smaller displacement, or some of the working pumps work and the rest do not work. The first merging valve 6.3 and the second merging valve 7.3 adjust the appropriate opening according to the working flow of the first working pump 1 and the fourth working pump 4 to allow the flow to enter the oil cylinder. When not working, the first merging valve 6.3 or the second merging valve 7.3 corresponding to the working pump remains in the disconnected state, so that the standby flow returns to the oil tank 11.

[0040] Furthermore, to fully utilize the boom's potential energy and conserve energy, the first and second boom working links 6.1 and 7.1 are both set to the second right working position. The third and seventh proportional solenoid valves 6.14 and 7.14 operate in the second right working position at the second current value. Both the large and small chambers of boom cylinder 8 are connected to oil return ports T1 and T2 through the first and second boom working links 6.1 and 7.1, and thus to the oil tank 11. As boom cylinder 8 retracts under its own weight, some oil in the large chamber enters the small chamber through the first and second boom working links 6.1 and 7.1, and some returns to the oil tank 11. During this process, the first and second merging valves 6.3 and 7.3 operate in the disconnected position. The first, second, third, and fourth working pumps 1, 2, 3, and 4 are in standby displacement, returning to the oil tank 11 at a low flow rate and not participating in any operation. When the falling speed is fast, oil can be added from the oil tank 11 to the small cavity through the first oil supply valve 6.7 / the second oil supply valve 7.7 to prevent the small cavity from being sucked empty.

[0041] Bucket collection and tipping: The bucket retraction and tipping actions are similar to the boom lifting and lowering working principles, but no floating function is set.

[0042] Working device compound action: Boom lifting + bucket retraction: The electric control handle 17 is actuated to send an angle signal to the controller 15. The controller 15 converts the angle signal into different current signals and sends them to the first working pump 1, the second working pump 2, the third working pump 3 and the fourth working pump 4, and sends electrical signals to the third proportional solenoid valve 6.14, the fourth proportional solenoid valve 6.15, the seventh proportional solenoid valve 7.14 and the eighth proportional solenoid valve 7.15.

[0043] First working valve 6: The second proportional solenoid valve 6.13 is energized, the first boom working link 6.1 works in the left working position, the oil of the second working pump 2 reaches the large chamber of the boom cylinder 8 through the oil inlet P1, the first non-return valve 6.5, the first boom working link 6.1, the first load holding valve 6.12, and the working oil port Ab1, and the oil of the small chamber of the boom cylinder 8 returns to the oil tank 11 through the working oil port Bb1, the first boom working link 6.1, and the return oil port T1; valve 6.9 and the first proportional solenoid valve 6.10 are energized, the first dump bucket working link 6.2 works in the left working position, and the first working pump The oil in the bucket cylinder 9 reaches the large chamber through the oil inlet P2, the second one-way valve 6.9, the first bucket working link 6.2, and the working oil port Ac1. The oil in the small chamber of the bucket cylinder 9 returns to the oil tank 11 through the working oil port Bc1, the first bucket working link 6.2, and the return oil port T1. During this process, the first converging proportional solenoid valve 6.11 is de-energized, and the first converging valve 6.3 is in the disconnected position, isolating the P1 oil inlet from the P2 oil inlet. The second working pump 2 supplies oil to the first boom working link 6.1 alone, and the first working pump 1 supplies oil to the first bucket working link 6.2 alone.

[0044] Similarly, the second working valve 7: the sixth proportional solenoid valve 7.13 is energized, the second boom working link 7.1 works in the left working position, the oil of the third working pump 3 reaches the large chamber of the boom cylinder 8 through the oil inlet P3, the third non-return valve 7.5, the second boom working link 7.1, the second load holding valve 7.12, and the working oil port Ab2, and the oil of the small chamber of the boom cylinder 8 returns to the oil tank 11 through the working oil port Bb2, the second boom working link 7.1, and the return oil port T2; the fifth proportional solenoid valve 7.10 is energized, the second dump bucket working link 7.2 works in the left working position, and the fourth working pump The oil flows through the oil inlet P4, the fourth one-way valve 7.9, the second bucket working link 7.2, and the working oil port Ac2 to the large chamber of the bucket cylinder 9. The oil flows through the small chamber of the bucket cylinder 9 to the working oil port Bc2, the second bucket working link 7.2, and the oil return port T2 to the oil tank 11. During this process, the second merging proportional solenoid valve 7.11 is de-energized and the second merging valve 7.3 is in the off position, isolating the P3 oil inlet from the P4 oil inlet. The third working pump 3 supplies oil to the second boom working link 7.1 alone, and the fourth working pump 4 supplies oil to the second bucket working link 7.2 alone.

[0045] Through the above process, during the compound action, the second working pump 2 and the third working pump 3 supply oil to the boom cylinder 8 through the first working valve 6 and the second working valve 7 respectively, and the first working pump 1 and the fourth working pump 4 supply oil to the bucket cylinder 9 through the first working valve 6 and the second working valve 7 respectively, to realize the compound action of boom lifting + bucket retracting, and the first working pump 1, the second working pump 2, the third working pump 3 and the fourth working pump 4 are completely decoupled, and the displacement can be controlled independently. Each working joint is controlled by a separate proportional solenoid valve, and the opening degree of the working joint is adjusted independently to realize the decoupling of the compound action, effectively avoid the problems of uneven flow distribution and poor action coordination caused by load differences in the compound action, and improve the smoothness of the action. In addition, when the first boom working link 6.1 and the second boom working link 7.1 are in the floating working position, the first working pump 1 and the second working pump 2 can be combined to supply oil to the first bucket working link 6.2, and the third working pump 3 and the fourth working pump 4 can be combined to supply oil to the second bucket working link 7.2, and jointly supply oil to the bucket cylinder 9, realizing the combined action of the boom floating and falling and the bucket tipping. The independent control of the first working pump 1, the second working pump 2, the third working pump 3 and the fourth working pump 4 and each working link greatly improves the control freedom.

[0046] Combined action of steering and working device: The steering operating mechanism 16 and the electric control handle 17 operate simultaneously, sending signals to the controller 15. The controller converts the signals into different electrical signals and sends them to the steering pump 12, the first working pump 1, the second working pump 2, the third working pump 3, the fourth working pump 4, the steering control valve 13, the first working valve 6, and the second working valve 7. Because the steering system and the working system are independent of each other, during this composite action, the controller independently controls the steering pump 12 and the steering control valve 13 to achieve the steering action, and independently controls the first working pump 1, the second working pump 2, the third working pump 3, the fourth working pump 4, the first working valve 6, and the second working valve 7 to achieve the working device action, without affecting each other.

[0047] To sum up, in the hydraulic system of this embodiment, the steering system and the working system are independent of each other, avoiding steering failure or malfunction caused by unreasonable flow distribution during the combined action of steering and working device; the working system adopts a multi-pump and multi-valve design, and every two working pumps supply oil to one working valve. The number of pumps and valves can be freely selected according to the system flow requirements to meet the hydraulic system requirements of super-large loaders of different tonnages, and the system has a wide range of applications; in addition, the working valve has a dual oil inlet design, and the flow capacity is strong under the same valve body specifications; every two working pumps supply oil to the working valve separately through the dual oil inlets of the same working valve, instead of merging before the valve and then supplying oil through one oil inlet, thereby realizing decoupling between the working pumps and having a high degree of independent control freedom.

[0048] This embodiment adopts an integrated electronically controlled pilot design. Each working link is controlled by two proportional solenoid valves integrated on the working valve to control the reversing. The working links are independent of each other and do not affect each other. The merging valve can realize that the flow of a single working pump can supply oil to different working links separately in the working valve, so that different working links in the same working valve are decoupled. The merging valve can also realize that two working pumps connected to the same working valve merge in the valve and then supply oil to a certain working link, meeting the requirements of large flow and fast speed of single action of the corresponding actuator. In addition, working links of different actuators are arranged on the same working valve. The working links are independent of each other. Multiple working links of the same actuator are arranged on multiple working valves, and the flow of multiple working links can be merged after the valves to enter the cylinder, thereby improving the flow level. The same actuator is controlled by multiple working links arranged on different working valves. One or more of the links can be selectively controlled to control the oil inlet, and the remaining working links can control the oil return, thereby realizing decoupling between the oil inlet and return of the same actuator. The return oil back pressure can be independently adjusted without affecting the oil inlet, thereby improving the smoothness of the action. Each working pump is independently controlled, and a portion of the working pumps can be selectively used to supply the first action of the actuator, while the remaining working pumps supply the second action of the actuator. Independent control improves the coordination of the compound action; the boom working link on the working valve is set with a floating lowering working position to meet the function of lowering the boom by relying on potential energy. The working pump does not need to supply oil to the boom, reducing energy consumption.

[0049] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the technical principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A large loader independently controlled hydraulic system, characterized in that: include: a first working pump and a second working pump; A first working valve, with port P1 connected to the second working pump and port P2 connected to the first working pump; a first converging valve is provided between ports P1 and P2 of the first working valve; the first working valve includes a first boom working link and a first bucket working link; When the first merging valve is open and the first boom working joint is in the working position, the flow of the first working pump can merge with the second working pump at the P1 port and supply oil to the boom cylinder through the first boom working joint; When the first merging valve is open and the first dump bucket working link is in the working position, the flow of the second working pump can merge with the first working pump at the P2 port and supply oil to the dump bucket cylinder through the first dump bucket working link; When the first combining valve is closed and the first boom working link and the first bucket working link are both in the working position, the first working pump supplies oil to the bucket cylinder through the first bucket working link, and the second working pump supplies oil to the boom cylinder through the first boom working link.

2. The large loader independent control hydraulic system according to claim 1, characterized in that: The first movable arm working joint has a left working position, a first right working position and a second right working position; When the first boom working link is in the left working position, the hydraulic oil at the P1 port can pass through the first one-way valve, the first boom working link, the first load holding valve, and the Ab1 port of the first working valve to reach the rodless chamber of the boom cylinder; When the first boom working link is in the right first working position, the hydraulic oil at the P1 port can pass through the first one-way valve, the first boom working link, and the Bb1 port of the first working valve to reach the rod chamber of the boom cylinder; When the first boom working link is in the second right working position, the rodless chamber of the boom cylinder is connected to the return oil port of the first boom working link through the Ab1 port of the first working valve, and the rod chamber of the boom cylinder is connected to the return oil port of the first boom working link through the Bb1 port of the first working valve. At this time, if the first bucket working link is in the working position, when the first merging valve is opened, the first working pump and the second working pump can merge to supply oil to the bucket cylinder through the first bucket working link. When the first merging valve is closed, the first working pump can supply oil to the bucket cylinder through the first bucket working link.

3. The large loader independent control hydraulic system according to claim 2, characterized in that: Also includes: The second proportional solenoid valve and the third proportional solenoid valve are respectively connected to the left end and the right end of the first boom working link to control the first boom working link to switch between the left working position, the first right working position and the second right working position.

4. The large loader independent control hydraulic system according to claim 1, characterized in that: The first dump bucket working link has a left working position and a right working position; When the first bucket working link is in the left working position, the hydraulic oil at the P2 port can pass through the second one-way valve, the first bucket working link and the Ac1 port of the first working valve to reach the rodless chamber of the bucket cylinder; When the first bucket working link is in the right working position, the hydraulic oil at the P2 port can reach the rod chamber of the bucket cylinder through the second one-way valve, the first bucket working link and the Bc1 port of the first working valve.

5. The large loader independent control hydraulic system according to claim 4, characterized in that: Also includes: The first proportional solenoid valve and the fourth proportional solenoid valve are respectively connected to the left end and the right end of the first dump bucket working link to control the first dump bucket working link to switch between the left working position and the right working position.

6. The large loader independent control hydraulic system according to claim 1, characterized in that: Also includes: The third working pump and the fourth working pump, The second working valve has a P3 port connected to the third working pump and a P4 port connected to the fourth working pump. A second combining valve is provided between the P3 and P4 ports of the second working valve. The second working valve includes a second boom working link and a second bucket working link. When the first merging valve and the second merging valve are both open and the first boom working link and the second boom working link are both in the working position, the flow of the fourth working pump can merge with the third working pump at the P3 port and pass through the second boom working link to cooperate with the first working pump and the second working pump to supply oil to the boom cylinder; When the first merging valve and the second merging valve are both open and the first and second dump bucket working links are both in the working position, the flow of the third working pump can merge with the fourth working pump at the P4 port and pass through the second dump bucket working link to cooperate with the first and second working pumps to supply oil to the dump bucket cylinder; When the second combining valve is closed and the first boom working link and the first bucket working link are both in the working position, the third working pump can supply oil to the boom cylinder through the second boom working link, and the fourth working pump can supply oil to the bucket cylinder through the second bucket working link.

7. The large loader independent control hydraulic system according to claim 6, characterized in that: The second movable arm working joint has a left working position, a first right working position and a second right working position; When the second boom working link is in the left working position, the hydraulic oil at the P3 port can pass through the third one-way valve, the second boom working link, the second load holding valve, and the Ab2 port of the second working valve to reach the rodless chamber of the boom cylinder; When the second boom working joint is in the right first working position, the hydraulic oil at the P3 port can pass through the third one-way valve, the second boom working joint, and the Bb2 port of the second working valve to reach the rod chamber of the boom cylinder; When the second boom working link is in the second right working position, the rodless chamber of the boom cylinder is connected to the return oil port of the second boom working link through the Ab2 port of the second working valve, and the rod chamber of the boom cylinder is connected to the return oil port of the first boom working link through the Bb2 port of the second working valve. At this time, if the second bucket working link is in the working position, when the second merging valve is opened, the third working pump and the fourth working pump can merge to supply oil to the bucket cylinder through the first bucket working link. When the second merging valve is closed, the fourth working pump can supply oil to the bucket cylinder through the second bucket working link.

8. The large loader independent control hydraulic system according to claim 7, characterized in that: The second dump bucket working link has a left working position and a right working position; When the second bucket working link is in the left working position, the hydraulic oil at the P4 port can pass through the fourth one-way valve, the second bucket working link and the Ac2 port of the second working valve to reach the rodless chamber of the bucket cylinder; When the second bucket working link is in the right working position, the hydraulic oil at the P4 port can reach the rod chamber of the bucket cylinder through the fourth one-way valve, the second bucket working link and the Bc2 port of the second working valve.

9. The large loader independent control hydraulic system according to claim 8, characterized in that: Also includes: a sixth proportional solenoid valve and a seventh proportional solenoid valve, connected to the left end and the right end of the second boom working link, respectively, to control the second boom working link to switch between the left working position, the first right working position, and the second right working position; a fifth proportional solenoid valve and an eighth proportional solenoid valve, connected to the left end and the right end of the second dump bucket working link, respectively, to control the second dump bucket working link to switch between the left working position and the right working position; The first merging proportional solenoid valve and the second merging proportional solenoid valve are respectively connected to the first merging valve and the second merging valve to control the valve port opening.

10. The large loader independent control hydraulic system according to claim 6, characterized in that: Also includes: Steering pump, connected to the steering cylinder through the steering control valve; A controller is connected to a steering operating mechanism, a power unit and an electric control handle; the steering operating mechanism is used to control the steering pump to drive the steering cylinder; the power unit is used to drive the first working pump, the second working pump, the third working pump and the fourth working pump; the electric control handle is used to control the first working valve and the second working valve to enable the boom cylinder and the bucket cylinder to perform specified actions.

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