A large loader independent control hydraulic system

Abstract

The present application relates to the technical field of loaders, in particular to a large loader independent control hydraulic system. It comprises a first working pump and a second working pump; a first working valve, P1 port is connected with the second working pump, P2 port is connected with the first working pump; a first confluence valve is arranged between P1 port and P2 port of the first working valve; the first working valve comprises a first boom working link and a first bucket working link; the first confluence valve is used to make the flow of the first working pump and the second working pump confluence in the first working valve to supply the same working link, so as to meet the demand of large flow and high speed of the boom cylinder or the bucket cylinder; meanwhile, the different working links can be supplied respectively to realize the composite action of the boom and the bucket, meet the different flow demand of different working links, the working pump and the execution mechanism are independently controlled, and each working link can obtain stable flow supply.

Description

Technical Field

[0001] This invention relates to the field of loader technology, and more specifically to an independent control hydraulic system for a large loader. Background Technology

[0002] The hydraulic system of a loader mainly includes a steering system and a working system. The steering pump is mainly responsible for supplying oil to the steering cylinder through the steering control valve to control the vehicle's steering. The working pump is mainly responsible for supplying oil to the boom and bucket cylinders through the working control valve to control the loading and unloading operations of the working device.

[0003] To meet the high flow rate requirements of ultra-large loaders, the working system is often equipped with multiple working pumps and multiple working valves. The working pumps often adopt a tandem pump configuration, where the flow is combined before being supplied to the working valves. This results in strong coupling between the pumps, and flow distribution relies on the stroke limits of each working link on the working valve, increasing throttling losses and energy consumption. Some products use a series-parallel configuration of working valves, relying on the valve core shoulder to control the on / off state of the oil circuit. This prioritizes flow distribution to the working links closer to the oil inlet, while the working links further away receive little or no flow. This limits flow distribution capability and results in higher system throttling losses. Summary of the Invention

[0004] The purpose of this invention is to provide an independently controlled hydraulic system for a large loader. A first confluence valve allows the flow rates of the first and second working pumps to be combined within the first working valve to supply the same working link (either the first boom working link or the first dumping working link), thus meeting the high flow rate and high speed requirements of the boom cylinder or dumping cylinder. Simultaneously, it can also supply different working links separately (the first working pump supplies the first dumping working link, and the second working pump supplies the first boom working link) to achieve combined boom and dumping actions, satisfying the different flow rate requirements of different working links. The working pumps (first and second working pumps) and the actuators (boom cylinder and dumping cylinder) are independently controlled, ensuring a stable flow rate supply to each working link (the first boom working link and the first dumping working link).

[0005] To achieve the above objectives, the present invention adopts the following technical solution:

[0006] In a first aspect, the present invention provides an independently controlled hydraulic system for a large loader, comprising:

[0007] First working pump and second working pump;

[0008] The first working valve has a P1 port connected to the second working pump and a P2 port connected to the first working pump; a first confluence valve is provided between the P1 port and the P2 port of the first working valve; the first working valve includes a first boom working link and a first tipping bucket working link.

[0009] When the first confluence valve is open and the first boom working link is in the working position, the flow rate of the first working pump can be combined with the second working pump at port P1 and supply oil to the boom cylinder through the first boom working link.

[0010] When the first confluence valve is open and the first tipping bucket working link is in the working position, the flow rate of the second working pump can be combined with that of the first working pump at port P2 and supply oil to the tipping bucket cylinder through the first tipping bucket working link.

[0011] When the first confluence valve is closed and both the first boom working link and the first bucket working link are 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.

[0012] Optionally, the first boom working link has a left working position, a right first working position, and a right second working position;

[0013] When the first boom working link is in the left working position, the hydraulic oil at port P1 can reach the rodless chamber of the boom cylinder through the Ab1 port of the first check valve, the first boom working link, the first load holding valve, and the first working valve.

[0014] When the first boom working link is in the right working position, the hydraulic oil at port P1 can reach the rod chamber of the boom cylinder through the first check valve, the first boom working link, and port Bb1 of the first working valve.

[0015] When the first boom working link is in the right second 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 confluence valve is open, the first working pump and the second working pump can merge and supply oil to the bucket cylinder through the first bucket working link. When the first confluence valve is closed, the first working pump can supply oil to the bucket cylinder through the first bucket working link.

[0016] Optionally, it also includes:

[0017] The second and third proportional solenoid valves are connected to the left and right ends of the first boom working link, respectively, to control the switching of the first boom working link between the left working position, the first right working position, and the second right working position.

[0018] Optionally, the first tipping bucket working link has a left working position and a right working position;

[0019] When the first tipping bucket working link is in the left working position, the hydraulic oil at port P2 can reach the rodless chamber of the tipping bucket cylinder through the second check valve, the first tipping bucket working link and the Ac1 port of the first working valve.

[0020] When the first tipping bucket working link is in the right working position, the hydraulic oil at port P2 can reach the rod chamber of the tipping bucket cylinder through the second check valve, the first tipping bucket working link, and port Bc1 of the first working valve.

[0021] Optionally, it also includes:

[0022] The first proportional solenoid valve and the fourth proportional solenoid valve are respectively connected to the left and right ends of the first tipping bucket working unit to control the switching of the first tipping bucket working unit between the left working position and the right working position.

[0023] Optionally, it also includes:

[0024] The third and fourth working pumps,

[0025] 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 confluence 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 tipping bucket working link.

[0026] When both the first and second confluence valves are open and both the first and second boom working links are in the working position, the flow rate of the fourth working pump can be combined with the third working pump at port P3 and, through the second boom working link, work in conjunction with the first and second working pumps to supply oil to the boom cylinder.

[0027] When both the first and second confluence valves are open and both the first and second tipping bucket working links are in the working position, the flow rate of the third working pump can be combined with that of the fourth working pump at port P4 and, through the second tipping bucket working link, work together with the first and second working pumps to supply oil to the tipping bucket cylinder.

[0028] When the second confluence valve is closed and both the first boom working link and the first bucket working link are 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.

[0029] Optionally, the second boom working link has a left working position, a right first working position, and a right second working position;

[0030] When the second boom working link is in the left working position, the hydraulic oil at port P3 can reach the rodless chamber of the boom cylinder through the third check valve, the second boom working link, the second load holding valve, and port Ab2 of the second working valve.

[0031] When the second boom working link is in the right working position, the hydraulic oil at port P3 can reach the rod chamber of the boom cylinder through the third check valve, the second boom working link, and port Bb2 of the second working valve.

[0032] When the second boom working link is in the right second working position, the rodless chamber of the boom cylinder is connected to the return 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 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 confluence valve is open, the third and fourth working pumps can combine to supply oil to the bucket cylinder through the first bucket working link, and when the second confluence valve is closed, the fourth working pump can supply oil to the bucket cylinder through the second bucket working link.

[0033] Optionally, the second tipping bucket working link has a left working position and a right working position;

[0034] When the second tipping bucket working link is in the left working position, the hydraulic oil at port P4 can reach the rodless chamber of the tipping bucket cylinder through the fourth check valve, the second tipping bucket working link, and the Ac2 port of the second working valve.

[0035] When the second tipping bucket working link is in the right working position, the hydraulic oil at port P4 can reach the rod chamber of the tipping bucket cylinder through the fourth check valve, the second tipping bucket working link, and port Bc2 of the second working valve.

[0036] Optionally, it also includes:

[0037] The sixth and seventh proportional solenoid valves are connected to the left and right ends of the second boom working link, respectively, to control the switching of the second boom working link between the left working position, the first right working position, and the second right working position.

[0038] The fifth and eighth proportional solenoid valves are respectively connected to the left and right ends of the second tipping bucket working link to control the switching of the second tipping bucket working link between the left working position and the right working position.

[0039] The first and second merging proportional solenoid valves are connected to the first and second merging valves respectively to control the valve opening.

[0040] Optionally, it also includes:

[0041] The steering pump is connected to the steering cylinder via a steering control valve.

[0042] The 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 make the boom cylinder and the tipping cylinder perform specified actions.

[0043] Compared with the prior art, the present invention has the following beneficial effects:

[0044] 1. This invention allows the flow rates of the first working pump and the second working pump to be combined within the first working valve to supply the same working link (first boom working link or first bucket working link), thereby meeting the high flow rate and high speed requirements of the boom cylinder or the bucket cylinder. At the same time, it can also supply 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 combined boom and bucket actions, meeting the different flow rate requirements of different working links. The working pumps (first working pump and second working pump) and the actuators (boom cylinder and bucket cylinder) are independently controlled, and each working link (first boom working link and first bucket working link) can obtain a stable flow rate supply.

[0045] 2. In this invention, the steering system and the working system are independent of each other and are controlled separately by the controller, which can avoid steering failure caused by uneven load when the steering and working devices perform combined actions. Each working valve is supplied with oil by two working pumps, and each working link is controlled separately by an independent proportional solenoid valve. The oil from each pair of working pumps enters the same working valve. The working valve is equipped with a confluence valve, which allows the flow rates of the two pumps to be combined within the valve to supply the same working link to meet the high flow rate and high speed requirements of the actuator. At the same time, it can also supply oil to different working links separately to meet the different flow rate requirements of different working links within the same valve group. Each working pump and actuator is independently controlled.

[0046] 3. In this invention, different actuator working links are arranged on the same working valve. The same actuator is controlled by multiple working links and distributed on different working valves (the tipping cylinder is controlled by the first tipping working link of the first working valve and the second tipping working link of the second working valve, and the boom cylinder is the same). This realizes independent control of multiple working links of the same actuator, decoupling between working links, and thus controlling the inlet and return oil separately. This ensures the speed of the actuator while facilitating back pressure adjustment, reducing throttling losses, and improving the smoothness of operation. In addition, when compound actions are achieved, a number of working pumps can control the working links of the same actuator through multiple working valves to control that actuator (the first working pump controls the first bucket working link through the first working valve, and the fourth working pump controls the second bucket working link through the second working valve simultaneously; the boom cylinder is similarly controlled. Alternatively, the first and second working pumps can both supply oil to the boom cylinder through the first working valve (similarly, the third and fourth working pumps can also supply oil to the boom cylinder through the second working valve), while the third working pump supplies oil to the boom cylinder through the second working valve, and the fourth working pump supplies oil to the bucket cylinder through the second bucket working link, thus providing oil to the boom cylinder with three working pumps and one working pump for the bucket cylinder. Similarly, it is also possible to provide oil to the bucket cylinder with three working pumps and one working pump for the boom cylinder). The remaining working pumps control another actuator, and each actuator's action is controlled independently, effectively improving action coordination, reducing control complexity, and shortening the overall machine commissioning cycle. Attached Figure Description

[0047] Figure 1 This is a hydraulic schematic diagram of the independent control hydraulic system of the large loader in Example 1;

[0048] Figure 2 for Figure 1 Hydraulic schematic diagram of the first working valve in the system.

[0049] Figure 3 for Figure 1 The hydraulic schematic diagram of the second working valve in the system.

[0050] The following are the labels in the diagram: 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. Oil tank; 12. Steering pump; 13. Steering control valve; 14. Steering cylinder; 15. Controller; 16. Steering operating mechanism; 17. Electric control handle;

[0051] 6.1 First boom working link; 6.2 First bucket working link; 6.3 First confluence valve; 6.4 First relief valve; 6.5 First check valve; 6.6 First port relief valve; 6.7 First oil replenishment valve; 6.8 Second relief valve; 6.9 Second check valve; 6.10 First proportional solenoid valve; 6.11 First confluence 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;

[0052] 7.1 Second boom working link; 7.2 Second bucket working link; 7.3 Second confluence valve; 7.4 Third relief valve; 7.5 Third check valve; 7.6 Second port relief valve; 7.7 Second oil replenishment valve; 7.8 Fourth relief valve; 7.9 Fourth check valve; 7.10 Fifth proportional solenoid valve; 7.11 Second confluence 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 Implementation

[0053] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicating orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, are used only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the invention. Furthermore, the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined with "first," "second," etc., may explicitly or implicitly include one or more of that feature. In the description of this invention, unless otherwise stated, "a plurality of" means two or more. In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art will understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0054] The present invention will be further described below with reference to the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present invention, and should not be used to limit the scope of protection of the present invention. Example 1

[0055] To make the purpose, technical solution, and advantages of this invention patent clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments.

[0056] Combination Figure 1 This embodiment provides an independently controlled hydraulic system for a large loader, which includes a controller 15, a steering operating mechanism 16, an electric control handle 17, a power unit 18, a steering system, and a working system. The steering system and the working system are independent of each other. The steering system includes a steering pump 12, a steering control valve 13, a steering cylinder 14, etc. 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 dump cylinder 9, and an oil tank 11.

[0057] 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 drives the first working pump 1, second working pump 2, third working pump 3, fourth working pump 4, pilot pump 5, and steering pump 12 to operate, providing them with power. The steering operating mechanism 16 sends a steering signal to the controller 15, which converts it into a current signal and sends it to the steering control valve 13 and steering pump 12. The steering pump 12 adjusts to a suitable displacement and outputs a corresponding flow rate, and the steering control valve 13 opens to the 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. The electric control handle 17 transmits the angle signal to the controller 15, which converts it into an electrical signal and sends it to the first working valve 6, the second working valve 7, the first working pump 1, the second working pump 2, the third working pump 3, and the fourth working pump 4. This causes the first working pump 1, the second working pump 2, the third working pump 3, and the fourth working pump 4 to adjust to a suitable displacement and output the corresponding flow rate. The working links of the first working valve 6 and the second working valve 7 open to the corresponding degree, 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.

[0058] The first working valve 6 includes dual oil inlets P1 and P2, a first boom working link 6.1, a first tipping bucket working link 6.2, a first confluence valve 6.3, a first relief valve 6.4, a first check valve 6.5, a first port relief valve 6.6, a first replenishing valve 6.7, a second relief valve 6.8, a second check valve 6.9, a first proportional solenoid valve 6.10, a first confluence 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;

[0059] The second working valve 7 includes dual oil inlets P3 and P4, a second boom working link 7.1, a second tipping bucket working link 7.2, a second confluence valve 7.3, a third relief valve 7.4, a third check valve 7.5, a second port relief valve 7.6, a second replenishing valve 7.7, a fourth relief valve 7.8, a fourth check valve 7.9, a fifth proportional solenoid valve 7.10, a second confluence 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.

[0060] The first working pump 1 and the second working pump 2 supply pressurized oil to the first working valve 6 through inlets P2 and P1, respectively. The third working pump 3 and the fourth working pump 4 supply pressurized oil to the second working valve 7 through inlets P3 and P4, respectively. The flow direction of the main oil circuit is controlled by the different working positions of each working link on the first working valve 6 and the second working valve 7. The oil of the same working device is controlled to merge after the working valve and enter the large or small chamber of the boom cylinder 8 and the tipping cylinder 9, so that the cylinder can extend or retract.

[0061] Pilot pump 5 supplies pilot oil to the first working valve 6 and the second working valve 7 through ports Pf1 and Pf2 respectively. After passing 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, it acts on the end face of the working link to control the reversing action of the working link, thereby controlling the boom cylinder 8 and the tipping cylinder 9 to complete the corresponding actions. After passing through the first merging proportional solenoid valve 6.11 and the second merging proportional solenoid valve 7.11 respectively, it acts on the end face of the first merging valve 6.3 and the second merging valve 7.3 to control the reversing action of the first merging valve 6.3 and the second merging valve 7.3, thereby controlling whether the oil in 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 merge. Pilot pump 5 supplies oil to the first load holding valve 6.12 and the second load holding valve 7.12 respectively, and controls their opening and closing.

[0062] Figure 2The diagram shows the hydraulic principle of the first working valve 6. This working valve is equipped with the following components: a first boom working link 6.1, a first tipping bucket working link 6.2, a first confluence 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 confluence proportional solenoid valve 6.11, a first load holding valve 6.12, a first port relief valve 6.6, and a first replenishing valve 6.7. The first working valve 6 also has inlet ports P1 and P2, a return port T1, a pilot inlet port Pf1, a pilot return port Dr1, and working ports Abl, Bb1, Ac1, and Bc1. Oil inlet P1 is connected to return oil port T1 via the first boom working link 6.1 and the first bucket working link 6.2. Simultaneously, oil inlet P1 is connected to the first boom working link 6.1 via the first check valve 6.5. Oil inlet P1 is also connected to oil inlet P2 via the first confluence valve 6.3. Oil inlet P2 is connected to return oil port T1 via the first bucket working link 6.2 and the first boom working link 6.1. Simultaneously, oil inlet P2 is connected to the first bucket working link 6.2 via the second check valve 6.9. The oil from the pilot port Pf1 is fed through 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 to act on both ends of the first boom working link 6.1 and the first bucket working link 6.2, respectively. The hydraulic differential pressure between the two pilot oils controls the reversing action of the first boom working link 6.1 and the first bucket working link 6.2. The oil from the pilot port Pf1 is fed through the first merging proportional solenoid valve 6.11 to act on the end face of the first merging valve 6.3, controlling the reversing action of the first merging valve 6.3, and thus controlling whether the P1 port and the P2 port are connected.

[0063] Figure 3The diagram shows the hydraulic principle of the second working valve 7. This hydraulic valve is equipped with the following components: a second boom working link 7.1, a second tipping bucket working link 7.2, a second confluence 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 confluence proportional solenoid valve 7.11, a second load holding valve 7.12, a second port relief valve 7.6, and a second replenishing valve 7.7. The second working valve 7 also has inlet ports P3 and P4, a return port T2, a pilot inlet port Pf2, a pilot return port Dr2, and working ports Ab2, Bb2, Ac2, and Bc2. The P3 oil inlet is connected to the return oil port T2 via the second boom working link 7.1 and the second bucket working link 7.2. Simultaneously, the P3 oil inlet is connected to the second boom working link 7.1 via the third check valve 7.5, and the P3 oil inlet is also connected to the oil inlet P4 via the second confluence valve 7.3. The P4 oil inlet is connected to the return oil port T2 via the second bucket working link 7.2 and the second boom working link 7.1, and simultaneously, the P4 oil inlet is connected to the second bucket working link 7.2 via the fourth check valve 7.9. The oil from the pilot inlet Pf2 is fed through 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 to act on both ends of the second boom working link 7.1 and the second bucket working link 7.2, respectively. The hydraulic differential pressure between the two pilot oils controls the reversing action of the second boom working link 7.1 and the second bucket working link 7.2. The oil from the pilot inlet Pf2 is fed through the second merging proportional solenoid valve 7.11 to act on the end face of the second merging valve 7.3, controlling the reversing action of the second merging valve 7.3, and thus controlling whether the P3 oil port and the P4 oil port are connected.

[0064] The working oil port Ab1 of the first working valve 6 and the working oil port Ab2 of the second working valve 7 merge and are connected to the large chamber of the boom cylinder 8. The working oil port Bb1 of the first working valve 6 and the working oil port Bb2 of the second working valve 7 merge and are 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 merge and are connected to the large chamber of the tipping cylinder 9. The working oil port Bc1 of the first working valve 6 and the working oil port Bc2 of the second working valve 7 merge and are connected to the small chamber of the tipping cylinder 9.

[0065] To further explain in conjunction with the work process:

[0066] No steering response:

[0067] The steering operating mechanism 16 is not activated, the steering control valve 13 and the steering cylinder 14 are not activated, the controller 15 sends the minimum current value to the steering pump 12, so that it works at the minimum displacement, and discharges a small amount of flow back to the oil tank 11 through the steering control valve 13, and remains in standby state.

[0068] There is a steering action:

[0069] The steering 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 adjusts to a suitable 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.

[0070] The working device is not operating:

[0071] When the electric control handle 17 does not move, 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. All proportional solenoid valves have no current, and the first working valve 6 and the second working valve 7 operate in the neutral position. A small portion of the oil from the second working pump 2 returns to the oil tank 11 through the inlet P1 of the first working valve 6, the first boom working link 6.1, the first tipping bucket working link 6.2, and the return port T1. A small portion of the oil from the first working pump 1 returns to the oil tank 11 through the inlet P2 of the first working valve 6, the first tipping bucket working link 6.2, the first boom working link 6.1, and the return port T1. A small portion of the oil from the third working pump 3 returns to the oil tank 11 through the inlet P3 of the second working valve 7, the second boom working link 7.1, the second tipping bucket working link 7.2, and the return port T2. A small portion of the oil from the fourth working pump 4 returns to the oil tank 11 through the inlet P4 of the second working valve 7, the second tipping bucket working link 7.2, the second boom working link 7.1, and the return port T2.

[0072] The first confluence valve 6.3 and the second confluence valve 7.3 are two-position two-way proportional directional valves. When there is no action, the first confluence proportional solenoid valve 6.11 and the second confluence proportional solenoid valve 7.11 have no current, the first confluence valve 6.3 and the second confluence valve 7.3 are in the open 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.

[0073] Single action of working device:

[0074] Lever lifting:

[0075] When the electric control handle 17 is activated, it sends an angle signal to the controller 15. The controller 15 converts this signal into a 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. It also sends electrical signals to the third proportional solenoid valve 6.14, the seventh proportional solenoid valve 7.14, the first confluence proportional solenoid valve 6.11, and the second confluence proportional solenoid valve 7.11. The oil in the pilot inlet of Pf1 acts on the left end of the first boom working link 6.1 through the second proportional solenoid valve 6.13. The third proportional solenoid valve 6.14 is energized, and the oil in the pilot inlet of Pf1 is depressurized by the third proportional solenoid valve 6.14 and then acts on the right end of the first boom working link 6.1. Under the action of the pressure difference between the two ends, the first boom working link 6.1 changes direction 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 via the first merging valve 6.3, and 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 acts on 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, after being depressurized by the seventh proportional solenoid valve 7.14, acts on the right end of the second boom working link 7.1. Under the pressure difference between the two ends, the second boom working link 7.1 switches 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 oil from the P3 inlet via the second merging valve 7.3, and 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. After the oil flows into the large chamber of boom cylinder 8 through working ports Ab1 and Ab2, the oil in the small chamber of boom cylinder 8 reaches the first boom working link 6.1 and the second boom working link 7.1 through working ports Bb1 and Bb2 respectively, and then returns to the oil tank 11, thereby enabling boom cylinder 8 to extend and complete the boom lifting action.

[0076] During this process, the first merging proportional solenoid valve 6.11 and the second merging proportional solenoid valve 7.11 are energized and reversed. The oil in the pilot inlet of Pf1, after passing through the first merging proportional solenoid valve 6.11 and the second merging proportional solenoid valve 7.11, acts on the first merging valve 6.3 and the second merging valve 7.3 respectively. This causes the first merging valve 6.3 and the second merging valve 7.3 to adjust their openings according to the current value, so that an appropriate amount of oil in the P2 inlet merges with the oil inlet P1, and an appropriate amount of oil in the P4 inlet merges with the oil inlet P3, and all of them enter the second boom working link 7.1, which together supply the boom cylinder 8.

[0077] Through the above method, four working pumps—the first working pump 1, the second working pump 2, the third working pump 3, and the fourth working pump 4—can simultaneously supply oil to the boom cylinder 8, ensuring the ultra-high flow rate required for a single boom lifting action and achieving rapid movement. Furthermore, the four working pumps are independent of each other, and their flow rates can be adjusted individually. The first merging proportional solenoid valve 6.11 and the second merging proportional solenoid valve 7.11 are also independent, allowing for independent adjustment of the opening degrees of the first merging valve 6.3 and the second merging valve 7.3, respectively, so that the flow rates of the four working pumps are combined. Simultaneously, the second proportional solenoid valve 6.13, the third proportional solenoid valve 6.14, the sixth proportional solenoid valve 7.13, and the seventh proportional solenoid valve 7.14 can be adjusted independently to control the reversing displacement and opening degree of the first boom working link 6.1 and the second boom working link 7.1, thereby matching the appropriate flow rate and working link opening to the required speed of the boom cylinder 8.

[0078] Boom descent and floating descent:

[0079] Similarly, when the electric control handle 17 is activated, it sends an angle signal to the controller 15. The controller 15 converts this signal into a 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. It also sends electrical signals to the second proportional solenoid valve 6.13, the sixth proportional solenoid valve 7.13, the first merging proportional solenoid valve 6.11, and the second merging proportional solenoid valve 7.11. The second proportional solenoid valve 6.13 and the sixth proportional solenoid valve 7.13 receive the first current value, and the first boom working coupling 6.1 and the second boom working coupling 7.1 operate at their rightmost working positions. The flow rates of the first working pump 1 and the second working pump 2 are merged within the first working valve 6 via the first merging valve 6.3 and then reach the working port Bb1 at the rightmost working position of the first boom working coupling 6.1. Simultaneously, the flow rates of the third working pump 3 and the fourth working pump 4 are merged within the second working valve 7 via the second merging valve 7.3. After passing through the rightmost working position of the second boom working link 7.1, the oil reaches the working port Bb2. The flow rates of working 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 working ports Ab1 / Ab2, the open 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 ports T1 / T2, thereby realizing the retraction of the boom cylinder 8 and completing the boom lowering action. Because this process is under negative load, the falling speed is relatively fast under the weight of the boom and other actuators, and the required flow rate 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 small displacement, or some of the working pumps work while the others do not. The first confluence valve 6.3 and the second confluence valve 7.3 adjust the opening degree appropriately according to the working flow rate of the first working pump 1 and the fourth working pump 4, so that the flow rate enters the oil cylinder. When not working, the first confluence valve 6.3 or the second confluence valve 7.3 corresponding to the working pump remains in the open state, so that the standby flow rate returns to the oil tank 11.

[0080] In addition, to fully utilize the boom's potential energy and save energy, both the first boom working link 6.1 and the second boom working link 7.1 are equipped with a right-second working position. The third proportional solenoid valve 6.14 and the seventh proportional solenoid valve 7.14 operate in the right-second working position when they receive the second current value. The large and small chambers of the boom cylinder 8 are connected to the return oil ports T1 and T2 through the first boom working link 6.1 and the second boom working link 7.1, and then connected to the oil tank 11. When the boom cylinder 8 retracts under its own weight, part of the oil in the large chamber enters the small chamber through the first boom working link 6.1 and the second boom working link 7.1, and part returns to the oil tank 11. During this process, the first confluence valve 6.3 and the second confluence valve 7.3 operate in the off position, and the first working pump 1, the second working pump 2, the third working pump 3 and the fourth working pump 4 are in standby displacement, returning to the oil tank 11 at a small flow rate and not participating in the operation. When the falling speed is relatively fast, oil can be replenished from the oil tank 11 to the small cavity through the first oil replenishment valve 6.7 / second oil replenishment valve 7.7 to prevent the small cavity from sucking in air.

[0081] Bucket loading and unloading:

[0082] The tipping bucket's bucket retraction and tipping action are similar to the boom's lifting and lowering working principle, but it does not have a floating function.

[0083] Compound actions of the working device:

[0084] boom lifting + bucket retraction:

[0085] When the electric control handle 17 is activated, it sends an angle signal to the controller 15. The controller 15 converts the 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. It also 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.

[0086] First working valve 6: Second proportional solenoid valve 6.13 is energized, first boom working link 6.1 operates in the left working position, oil from second working pump 2 flows through inlet P1, first check valve 6.5, first boom working link 6.1, first load holding valve 6.12, and working port Ab1 to the large chamber of boom cylinder 8, oil from the small chamber of boom cylinder 8 flows through working port Bb1, first boom working link 6.1, and return port T1 to oil tank 11; Valve 6.9 and first proportional solenoid valve 6.10 are energized, first tipping bucket working link 6.2 operates in the left working position, first working pump... 1. The oil flows through the inlet P2, the second check valve 6.9, the first tipping bucket working link 6.2, and the working port Ac1 to the large chamber of the tipping bucket cylinder 9. The oil in the small chamber of the tipping bucket cylinder 9 flows through the working port Bc1, the first tipping bucket working link 6.2, and the return port T1 back to the oil tank 11. During this process, the first merging proportional solenoid valve 6.11 is not energized, and the first merging valve 6.3 is in the open position, so that the inlet P1 and the inlet P2 are isolated from each other. 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 tipping bucket working link 6.2 alone.

[0087] Similarly, when the second working valve 7 and the sixth proportional solenoid valve 7.13 are energized, the second boom working coupling 7.1 operates in the left working position. Oil from the third working pump 3 flows through inlet P3, the third check valve 7.5, the second boom working coupling 7.1, the second load holding valve 7.12, and working port Ab2 to the large chamber of the boom cylinder 8. Oil from the small chamber of the boom cylinder 8 flows through working port Bb2, the second boom working coupling 7.1, and return port T2 back to the oil tank 11. When the fifth proportional solenoid valve 7.10 is energized, the second tipping bucket working coupling 7.2 operates in the left working position, and the fourth working pump... 4. The oil flows through the inlet P4, the fourth check valve 7.9, the second tipping bucket working link 7.2, and the working port Ac2 to the large chamber of the tipping bucket cylinder 9. The oil in the small chamber of the tipping bucket cylinder 9 flows through the working port Bc2, the second tipping bucket working link 7.2, and the return port T2 back to the oil tank 11. During this process, the second merging proportional solenoid valve 7.11 is not energized, and the second merging valve 7.3 is in the open position, so that the oil inlet P3 and the oil inlet P4 are isolated from each other. The third working pump 3 supplies oil to the second boom working link 7.1 separately, and the fourth working pump 4 supplies oil to the second tipping bucket working link 7.2 separately.

[0088] 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 tipping cylinder 9 through the first working valve 6 and the second working valve 7, respectively. This achieves the compound action of boom lifting and bucket retraction. Furthermore, the first working pump 1, the second working pump 2, the third working pump 3, and the fourth working pump 4 are completely decoupled, allowing for independent control of their displacement. Each working link is controlled by a separate proportional solenoid valve, allowing for independent adjustment of the working link opening. This decoupling of the compound action effectively avoids uneven flow distribution and poor action coordination caused by load differences during the compound action, thus improving the smoothness of the action.

[0089] 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 merge to supply oil to the first bucket working link 6.2, and the third working pump 3 and the fourth working pump 4 can merge to supply oil to the second bucket working link 7.2, which together supply oil to the bucket cylinder 9, realizing the combined action of boom floating and falling and 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 degree of control freedom.

[0090] Combined steering and working device actions:

[0091] The steering mechanism 16 and the electric control handle 17 operate simultaneously, sending signals to the controller 15. The controller converts these 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, respectively. Since the steering system and the working system are independent of each other, during this combined operation, 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 operation, without affecting each other.

[0092] In summary, 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 when the steering and working devices perform combined actions. The working system adopts a multi-pump, multi-valve design, with two working pumps supplying 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 needs of ultra-large loaders of different tonnages, and the system has a wide range of applications. In addition, the working valve has a dual-inlet design, which has strong flow capacity under the same valve body specifications. Each pair of working pumps supplies oil to the working valve through the dual inlets of the same working valve, replacing the method of supplying oil through a single inlet after the flow before the valve is combined, realizing decoupling between working pumps and high degree of freedom in independent control.

[0093] This embodiment employs an integrated electronically controlled pilot design. Each working link is controlled by two proportional solenoid valves integrated on the working valve, ensuring that each working link is independent and does not affect the others. A confluence valve allows individual working pumps to supply oil to different working links separately within the working valve, decoupling different working links within the same working valve. The confluence valve also allows two working pumps connected to the same working valve to combine their flow within the valve and supply oil to a specific working link, meeting the high flow rate and high speed requirements of the corresponding actuators for single-action operation. Furthermore, different actuator working links are set on the same working valve, with each working link operating independently. Multiple working links of the same actuator are arranged on multiple working valves, allowing the flow rates of multiple working links to merge after the valve and enter the cylinder, improving the flow rate. The same actuator is controlled by multiple working links arranged on different working valves, allowing selective control of oil inlet by one or more links, while the remaining links control oil return, achieving decoupling between the inlet and return oil of the same actuator. This allows independent adjustment of the return oil back pressure without affecting the oil inlet, improving the smoothness of operation. Each working pump is independently controlled, allowing a select number of pumps to power actuator one while the remaining pumps power actuator two. This independent control improves the coordination of complex actions. The boom working link on the working valve is equipped with a floating lowering position, which allows the boom to be lowered using potential energy. This eliminates the need for the working pumps to supply oil to the boom, reducing energy consumption.

[0094] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A hydraulic system for independent control of a large loader, characterized in that, include: First working pump and second working pump; The first working valve has a P1 port connected to the second working pump and a P2 port connected to the first working pump; a first confluence valve is provided between the P1 port and the P2 port of the first working valve; the first working valve includes a first boom working link and a first tipping bucket working link. When the first confluence valve is open and the first boom working link is in the working position, the flow rate of the first working pump can be combined with the second working pump at port P1 and supply oil to the boom cylinder through the first boom working link. When the first confluence valve is open and the first tipping bucket working link is in the working position, the flow rate of the second working pump can be combined with that of the first working pump at port P2 and supply oil to the tipping bucket cylinder through the first tipping bucket working link. When the first confluence valve is closed and both the first boom working link and the first bucket working link are 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. The first boom working position has a left working position, a right first working position, and a right second working position; When the first boom working link is in the left working position, the hydraulic oil at port P1 can reach the rodless chamber of the boom cylinder through the Ab1 port of the first check valve, the first boom working link, the first load holding valve, and the first working valve. When the first boom working link is in the right working position, the hydraulic oil at port P1 can reach the rod chamber of the boom cylinder through the first check valve, the first boom working link, and port Bb1 of the first working valve. When the first boom working link is in the right second 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 confluence valve is open, the first working pump and the second working pump can combine to supply oil to the bucket cylinder through the first bucket working link. When the first confluence valve is closed, the first working pump can supply oil to the bucket cylinder through the first bucket working link.

2. The independent control hydraulic system for large loaders according to claim 1, characterized in that, Also includes: The second and third proportional solenoid valves are connected to the left and right ends of the first boom working link, respectively, to control the switching of the first boom working link between the left working position, the first right working position, and the second right working position.

3. The independent control hydraulic system for large loaders according to claim 1, characterized in that, The first tipping bucket working link has a left working position and a right working position; When the first tipping bucket working link is in the left working position, the hydraulic oil at port P2 can reach the rodless chamber of the tipping bucket cylinder through the second check valve, the first tipping bucket working link and the Ac1 port of the first working valve. When the first tipping bucket working link is in the right working position, the hydraulic oil at port P2 can reach the rod chamber of the tipping bucket cylinder through the second check valve, the first tipping bucket working link, and port Bc1 of the first working valve.

4. The independent control hydraulic system for large loaders according to claim 3, characterized in that, Also includes: The first proportional solenoid valve and the fourth proportional solenoid valve are respectively connected to the left and right ends of the first tipping bucket working unit to control the switching of the first tipping bucket working unit between the left working position and the right working position.

5. The independent control hydraulic system for large loaders according to claim 1, characterized in that, Also includes: The third and fourth working pumps, 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 confluence 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 tipping bucket working link. When both the first and second confluence valves are open and both the first and second boom working links are in the working position, the flow rate of the fourth working pump can be combined with the third working pump at port P3 and, through the second boom working link, work in conjunction with the first and second working pumps to supply oil to the boom cylinder. When both the first and second confluence valves are open and both the first and second tipping bucket working links are in the working position, the flow rate of the third working pump can be combined with that of the fourth working pump at port P4 and, through the second tipping bucket working link, work together with the first and second working pumps to supply oil to the tipping bucket cylinder. When the second confluence valve is closed and both the first boom working link and the first bucket working link are 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.

6. The independent control hydraulic system for large loaders according to claim 5, characterized in that, The second boom working position has a left working position, a right first working position, and a right second working position; When the second boom working link is in the left working position, the hydraulic oil at port P3 can reach the rodless chamber of the boom cylinder through the third check valve, the second boom working link, the second load holding valve, and port Ab2 of the second working valve. When the second boom working link is in the right working position, the hydraulic oil at port P3 can reach the rod chamber of the boom cylinder through the third check valve, the second boom working link, and port Bb2 of the second working valve. When the second boom working link is in the right second working position, the rodless chamber of the boom cylinder is connected to the return 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 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 confluence valve is open, the third and fourth working pumps can combine to supply oil to the bucket cylinder through the first bucket working link, and when the second confluence valve is closed, the fourth working pump can supply oil to the bucket cylinder through the second bucket working link.

7. The independent control hydraulic system for large loaders according to claim 6, characterized in that, The second tipping bucket working link has a left working position and a right working position; When the second tipping bucket working link is in the left working position, the hydraulic oil at port P4 can reach the rodless chamber of the tipping bucket cylinder through the fourth check valve, the second tipping bucket working link, and the Ac2 port of the second working valve. When the second tipping bucket working link is in the right working position, the hydraulic oil at port P4 can reach the rod chamber of the tipping bucket cylinder through the fourth check valve, the second tipping bucket working link, and port Bc2 of the second working valve.

8. The independent control hydraulic system for large loaders according to claim 7, characterized in that, Also includes: The sixth and seventh proportional solenoid valves are connected to the left and right ends of the second boom working link, respectively, to control the switching of the second boom working link between the left working position, the first right working position, and the second right working position. The fifth and eighth proportional solenoid valves are respectively connected to the left and right ends of the second tipping bucket working link to control the switching of the second tipping bucket working link between the left working position and the right working position. The first and second merging proportional solenoid valves are connected to the first and second merging valves respectively to control the valve opening.

9. The independent control hydraulic system for large loaders according to claim 5, characterized in that, Also includes: The steering pump is connected to the steering cylinder via a steering control valve. The 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 make the boom cylinder and the tipping cylinder perform specified actions.

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