Dual pump merge system and loader

Abstract

The application relates to the technical field of engineering machinery, and particularly discloses a double-pump confluence system and a loader, the double-pump confluence system comprising an oil tank, a steering module, an execution module and an interaction module, when the loader provided with the double-pump confluence system is working, the steering module and the execution module control the respective displacements when the interaction module is switched to the second mode, so that the steering module and the execution module respectively meet the respective pressure oil consumption; when the interaction module is switched to the first mode, the steering module and the execution module can realize signal interaction, thereby being capable of controlling the displacement of the load-sensitive variable pump and the displacement of the positive flow variable pump, avoiding the problems of insufficient flow or excessive flow in the system, and improving the energy-saving effect. Meanwhile, the steering module adopts a load-sensitive system and has the characteristics of high safety, and the execution module adopts a positive flow system, thereby realizing the energy-saving effect.

Description

Technical Field

[0001] This invention relates to the field of engineering machinery technology, and in particular to a dual-pump confluence system and a loader. Background Technology

[0002] Loaders are essential pieces of machinery in construction engineering, primarily used for shoveling, loading, transporting, and digging loose materials. Currently, to save energy, loader hydraulic systems generally employ a dual-pump confluence system, thereby reducing the cost of hydraulic components and simplifying their layout design.

[0003] Existing loader hydraulic systems generally employ the following systems: 1. Fixed displacement pump combined system: The advantage is that it utilizes the flow from the steering pump to simultaneously supply the working system. The disadvantage is that when there is no operation, the fixed displacement pump continues to output flow with the engine rotation, and the pump cannot adjust its displacement, resulting in energy consumption. 2. Steering single variable displacement combined system (steering load-sensitive system, working system fixed displacement pump): The advantage is that the steering pump uses a variable displacement pump, so the displacement of the variable displacement pump does not generate excess flow during fast rotation, slow rotation, and no steering, achieving energy conservation. It also utilizes the flow from the steering pump to simultaneously supply the working system. The disadvantage is that when there is no operation, the working fixed displacement pump continues to output flow with the engine rotation, and the pump cannot adjust its displacement, resulting in energy consumption. 3. Dual variable load-sensitive combined system: The advantage is that it allows both pumps to meet the required flow according to system needs, achieving on-demand supply and energy conservation. The disadvantage is that in load-sensitive systems, there is a ΔP loss; as load loaders become larger, the required system flow increases (the larger the pump displacement), and the greater the power loss. 4. An electronically controlled positive flow system based on an electric steering system (the steering system uses an electronic control system, and the working system uses a positive flow system). The advantage is the absence of ΔP loss, achieving energy savings. The disadvantage is that since the steering system is electronically controlled, if the electronic control fails, steering fails, posing a safety hazard (in construction machinery, steering must be prioritized to ensure safety). 5. A positive flow hydraulic system based on a load-sensitive electronically controlled pump. The advantage is that the steering system uses a load-sensitive system, ensuring high safety, and the working system uses a positive flow system, achieving energy savings. The disadvantage is that the electronically controlled steering pump and the working system do not interact, making it unable to sense the flow demand of the working system, potentially leading to insufficient or excessive flow, thus failing to achieve the desired energy savings. In the above dual-pump confluence systems, energy saving and reliability cannot be achieved simultaneously.

[0004] Therefore, a dual-pump confluence system is urgently needed to solve the above problems. Summary of the Invention

[0005] The purpose of this invention is to provide a dual-pump confluence system and a loader to solve the problem that energy saving and high reliability cannot be achieved simultaneously in existing dual-pump confluence systems in related technologies.

[0006] On one hand, the present invention provides a dual-pump confluence system, the dual-pump confluence system comprising:

[0007] tank;

[0008] The steering module includes a load-sensitive variable pump and a priority valve, wherein the oil tank, the load-sensitive variable pump, and the priority valve are connected in sequence;

[0009] The execution module includes a positive flow multi-way valve group, at least two execution cylinders, and a positive flow variable pump. The positive flow multi-way valve group includes at least two multi-way valves, and the at least two multi-way valves are connected to the at least two execution cylinders in a one-to-one correspondence to form a circulating fluid circuit. The pressure port of the positive flow multi-way valve group is connected to the EF port of the priority valve, and the oil outlet of the positive flow variable pump is connected to the pressure port of the positive flow multi-way valve group.

[0010] The interaction module includes a first mode and a second mode. In the first mode, the pressure of the load pressure of at least two of the actuator cylinders and the pressure at the LS interface of the priority valve are selected, and the one with the highest oil pressure is connected to the control port of the pressure compensation valve of the load-sensitive variable pump. In the second mode, the LS interface of the priority valve is connected to the control port of the pressure compensation valve.

[0011] As a preferred technical solution for the dual-pump confluence system, the actuator is provided with two cylinders, namely a boom cylinder and a bucket cylinder;

[0012] The positive flow multi-way valve group includes two multi-way valves, namely a front valve and a rear valve. The front valve and the bucket cylinder are connected to form a circulating fluid circuit, and the rear valve and the boom cylinder are connected to form a circulating fluid circuit. The front valve and the rear valve are connected in series. The pressure port of the front valve is connected to the EF port of the priority valve, and the outlet of the positive flow variable pump is connected to the pressure port of the front valve.

[0013] In the first mode, the interaction module selects the one with the highest oil pressure among the inlet of the boom cylinder, the inlet of the bucket cylinder, and the LS interface of the priority valve, and connects it to the control port of the pressure compensation valve of the load-sensitive variable pump.

[0014] As a preferred technical solution for the dual-pump confluence system, the interaction module includes a first shuttle valve, a switching valve, and a second shuttle valve. The first input port A and the first input port B of the first shuttle valve are respectively connected to the inlet of the boom cylinder and the inlet of the bucket cylinder, and the first output port of the first shuttle valve is connected to the inlet of the switching valve.

[0015] The second input port A and the second input port B of the second shuttle valve are respectively connected to the outlet of the switching valve and the LS interface of the priority valve, and the second output port of the second shuttle valve is connected to the control port of the pressure compensation valve.

[0016] As a preferred technical solution for the dual-pump confluence system, the switching valve is a two-position three-way valve. The first port of the switching valve is connected to the first output port, the second port of the switching valve is connected to the second input port A of the second shuttle valve, and the third port of the switching valve is connected to the oil tank. The switching valve includes a first position and a second position. In the first position, the first port and the second port are connected. In the second position, the second port and the third port are connected.

[0017] As a preferred technical solution for the dual-pump confluence system, the steering module also includes a displacement sensor, which can monitor the swashplate tilt angle of the load-sensitive variable pump.

[0018] As a preferred technical solution for the dual-pump confluence system, the execution module further includes a pressure sensor, which is used to monitor the oil pressure at the pressure port of the positive flow multi-way valve group.

[0019] As a preferred technical solution for the dual-pump confluence system, the execution module further includes a pilot valve group, the working oil port of which is connected to the pilot end of the positive flow variable pump and the positive flow multi-way valve group respectively.

[0020] As a preferred technical solution for the dual-pump confluence system, the execution module further includes a pilot pump, the inlet of which is connected to the oil tank, and the outlet of which is connected to the inlet of the pilot valve assembly.

[0021] As a preferred technical solution for the dual-pump confluence system, the pilot valve group includes a pilot tube, a proportional relief valve, a first check valve, and an accumulator. One end of the pilot tube is connected to the pilot pump, and the other end of the pilot tube is connected to the oil supply port of the positive flow variable pump and the pilot end of the positive flow multi-way valve group, respectively. The first check valve is connected in series with the pilot tube and allows the oil in the pilot tube to flow from one end to the other. One end of the proportional relief valve is connected to the pilot tube, and the other end is connected to the oil tank. The accumulator is connected to the pilot tube, and the proportional relief valve and the accumulator are located on both sides of the first check valve, respectively.

[0022] As a preferred technical solution for the dual-pump confluence system, the front valve and the rear valve are connected in series.

[0023] On the other hand, the present invention provides a loader including the dual-pump confluence system of any of the above embodiments.

[0024] The beneficial effects of this invention are as follows:

[0025] This invention provides a dual-pump confluence system and a loader. The dual-pump confluence system includes an oil tank, a steering module, an execution module, and an interaction module. The steering module includes a load-sensitive variable pump and a priority valve, with the oil tank, load-sensitive variable pump, and priority valve connected sequentially. The execution module includes a positive flow multi-way valve group, at least two execution cylinders, and a positive flow variable pump. The positive flow multi-way valve group includes at least two multi-way valves, which are connected one-to-one with at least two execution cylinders to form a circulating fluid circuit. The pressure port of the positive flow multi-way valve group is connected to the EF port of the priority valve, and the outlet of the positive flow variable pump is connected to the pressure port of the positive flow multi-way valve group. The interaction module includes a first mode and a second mode. In the first mode, the pressure of the load pressure of at least two of the execution cylinders and the pressure at the LS interface of the priority valve are selected, and the one with the highest oil pressure is connected to the control port of the pressure compensation valve of the load-sensitive variable pump. In the second mode, the LS interface of the priority valve is connected to the control port of the pressure compensation valve. When a loader equipped with this dual-pump confluence system is operating, switching the interaction module to the second mode allows the steering and execution modules to work independently. Switching the interaction module to the first mode enables signal exchange between the steering and execution modules, thereby controlling the displacement of the load-sensitive variable pump and the positive flow variable pump. This prevents insufficient or excessive flow in the system, improving energy efficiency. Simultaneously, the steering module utilizes a load-sensitive system for high safety, and the execution module employs a positive flow system to achieve energy savings. Attached Figure Description

[0026] Figure 1 The fluid path of the dual-pump confluence system in this embodiment of the invention. Figure 1 ;

[0027] Figure 2 The fluid path of the dual-pump confluence system in this embodiment of the invention. Figure 2 .

[0028] In the picture:

[0029] 1. Fuel tank;

[0030] 2. Steering module; 21. Load-sensitive variable pump; 211. Pressure compensation valve; 22. Priority valve; 23. Steering gear; 24. Steering cylinder;

[0031] 3. Execution Module; 31. Positive Flow Multi-way Valve Assembly; 311. Front-end Valve; 312. Rear-end Valve; 313. Front-end Pilot Valve a; 314. Front-end Pilot Valve b; 315. Rear-end Pilot Valve a; 316. Rear-end Pilot Valve b; 32. Boom Cylinder; 33. Bucket Cylinder; 34. Positive Flow Variable Pump; 35. Pressure Sensor; 36. Pilot Valve Assembly; 361. Pilot Line; 362. Proportional Relief Valve; 363. First Check Valve; 364. Accumulator; 365. Filter; 366. Second Check Valve; 37. Pilot Pump;

[0032] 4. Interaction module; 41. First shuttle valve; 42. Switch valve; 43. Second shuttle valve. Detailed Implementation

[0033] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0034] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and for 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. Therefore, they should not be construed as limitations on the invention. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance. The terms "first position" and "second position" refer to two different positions. Furthermore, "above," "on top of," and "over" the first feature in relation to the second feature includes the first feature directly above and diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "under," and "below" the first feature in relation to the second feature includes the first feature directly below and diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0035] 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 can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0036] Embodiments of the present invention are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention.

[0037] like Figures 1-2 As shown, this embodiment provides a dual-pump confluence system, which includes an oil tank 1, a steering module 2, an execution module 3, and an interaction module 4. The steering module 2 includes a load-sensitive variable pump 21 and a priority valve 22. The oil tank 1, the load-sensitive variable pump 21, and the priority valve 22 are connected in sequence. The execution module 3 includes a positive flow multi-way valve group 31, at least two execution cylinders, and a positive flow variable pump 34. The positive flow multi-way valve group 31 includes at least two multi-way valves, which are connected one-to-one with at least two execution cylinders to form a circulating fluid circuit. The pressure port of the positive flow multi-way valve group 31 is connected to the priority valve 4. The EF port of valve 22 is connected, and the oil outlet of positive flow variable pump 34 is connected to the pressure oil port of positive flow multi-way valve group 31. The interaction module 4 includes a first mode and a second mode. In the first mode, the load pressure of at least two actuator cylinders and the pressure at the LS interface of priority valve 22, that is, the oil pressure at the oil inlet of the actuator cylinder and the oil pressure at the LS interface of priority valve 22, are selected to be connected to the control port of pressure compensation valve 211 of load sensitive variable pump 21. In the second mode, the LS interface of priority valve 22 is connected to the control port of pressure compensation valve 211.

[0038] When the loader equipped with the dual-pump confluence system is working, and the interaction module 4 is switched to the second mode, the steering module 2 and the execution module 3 work independently. At this time, the steering module 2 and the execution module 3 control their respective displacements so that the steering module 2 and the execution module 3 meet their respective pressure oil requirements.

[0039] When the interaction module 4 is switched to the first mode, the steering module 2 and the execution module 3 can exchange signals. At least two execution cylinders and the LS interface of the priority valve 22 are selected to connect the one with the highest oil pressure to the control port of the pressure compensation valve 211 of the load-sensitive variable pump 21, thereby controlling the load-sensitive variable pump 21 to adjust its own displacement. When the oil pressure at the inlet of the boom cylinder 32 or the inlet of the bucket cylinder 33 is higher than that at the LS interface of the priority valve 22, the load-sensitive variable pump 21 can provide pressure oil to the execution module 3. When the pressure at the LS interface of the priority valve 22 is higher than that at the inlet of the boom cylinder 32 or the inlet of the bucket cylinder 33, the load-sensitive variable pump 21 only provides pressure oil to the steering module 2.

[0040] Optionally, the steering module 2 adopts a load-sensitive system, which has high safety, and the execution module 3 adopts a positive flow system, which achieves energy-saving effect.

[0041] Optionally, the steering module 2 also includes a steering gear 23 and a steering cylinder 24. The steering gear 23 is connected to the priority valve 22, and the steering cylinder 24 is connected to the steering gear 23. The connection method between the load-sensitive variable pump 21, the priority valve 22, the steering gear 23, and the steering cylinder 24 is existing technology and will not be described in detail here.

[0042] In other embodiments, the steering module 2 only needs to be a steering system equipped with a load-sensitive variable pump 21.

[0043] Optionally, the steering module 2 can be a flow amplification system equipped with a load-sensitive variable pump 21.

[0044] When the interaction module 4 is in the first mode, the interaction module 4 first selects the inlet of two of the at least two actuator cylinders for comparison, selects the one with the largest pressure and compares it with the inlet of the other uncompared actuator cylinders until the pressure at the inlet of the actuator cylinder with the largest pressure is found. Then, the pressure is compared with the pressure value at the LS interface of the priority valve 22, and finally the signal with the largest pressure is transmitted to the control port of the pressure compensation valve 211.

[0045] Optionally, the actuator includes a boom cylinder 32 and a bucket cylinder 33; the positive flow multi-way valve group 31 includes two multi-way valves, namely a front valve 311 and a rear valve 312. The front valve 311 and the bucket cylinder 33 are connected to form a circulating fluid circuit, and the rear valve 312 and the boom cylinder 32 are connected to form a circulating fluid circuit. The front valve 311 and the rear valve 312 are connected in series. The pressure port of the front valve 311 is connected to the EF port of the priority valve 22, and the outlet of the positive flow variable pump 34 is connected to the pressure port of the front valve 311. In the first mode, the interaction module 4 selects the one with the highest oil pressure among the inlet of the boom cylinder 32, the inlet of the bucket cylinder 33, and the LS interface of the priority valve 22 and connects it to the control port of the pressure compensation valve 211 of the load-sensitive variable pump 21. In this embodiment, there are two hydraulic cylinders, namely boom cylinder 32 and bucket cylinder 33. In the first mode, the interaction module 4 first selects the one with the largest pressure value at the pressure port of boom cylinder 32 and bucket cylinder 33, and then compares the pressure value with the pressure value at the LS interface of priority valve 22 to select the one with the largest pressure to connect to the control port of pressure compensation valve 211 of load sensitive variable pump 21.

[0046] In this embodiment, the positive flow multi-way valve group 31 includes two multi-way valves, namely a front valve 311 and a rear valve 312. The front valve 311 and the rear valve 312 are connected in series. In other embodiments, the front valve 311 and the rear valve 312 can also be connected in parallel.

[0047] Optionally, in this embodiment, the positive flow multi-way valve group 31 is hydraulically controlled; in other embodiments, the positive flow multi-way valve group 31 may also be electrically controlled.

[0048] Optionally, the interaction module 4 includes a first shuttle valve 41, a switching valve 42, and a second shuttle valve 43. The first input port A and the first input port B of the first shuttle valve 41 are connected to the inlet of the boom cylinder 32 and the inlet of the bucket cylinder 33, respectively. The first output port of the first shuttle valve 41 is connected to the inlet of the switching valve 42. The second input port A and the second input port B of the second shuttle valve 43 are connected to the outlet of the switching valve 42 and the LS interface of the priority valve 22, respectively. The second output port of the second shuttle valve 43 is connected to the control port of the pressure compensation valve 211. In this embodiment, in the first mode, the switching valve 42 connects the first output port and the second input port A. At this time, the pressurized oil in the inlet of the boom cylinder 32 and the inlet of the bucket cylinder 33 flows to the first input port A and the first input port B of the first shuttle valve 41, respectively. The first shuttle valve 41 compares the oil pressure at the inlet of the boom cylinder 32 and the oil pressure at the inlet of the bucket cylinder 33. The inlet with the larger pressure value is connected to the second input port A of the second shuttle valve 43. Then, the second shuttle valve 43 compares the oil pressure at the second input port A and the second input port B, and connects the one with the larger pressure value to the control port of the pressure compensation valve 211. This allows the highest oil pressure among the three pressures—the inlet of the boom cylinder 32, the inlet of the bucket cylinder 33, and the LS interface of the priority valve 22—to be selected as the pressure signal and connected to the control port of the pressure compensation valve 211 of the load-sensitive variable pump 21. This controls the valve core of the pressure compensation valve 211 to adjust the swashplate tilt angle of the load-sensitive variable pump 21.

[0049] In other embodiments, optionally, when the number of actuators is three or more, the number of shuttle valves in the interaction module 4 is set to three or more, so that pressure values ​​can be compared between the three or more actuators and the LS interface of the priority valve 22.

[0050] Optionally, the switching valve 42 is a two-position three-way valve. The first port of the switching valve 42 is connected to the first output port, the second port of the switching valve 42 is connected to the second input port A of the second shuttle valve 43, and the third port of the switching valve 42 is connected to the oil tank 1. The switching valve 42 includes a first position and a second position. In the first position, the first and second ports are connected; in the second position, the second port is connected to the third port. In this embodiment, by moving the valve core of the switching valve 42, the switching valve 42 is adjusted between the first and second positions. When the switching valve 42 is in the first position, the first and second ports are connected, thereby connecting the first output port of the first shuttle valve 41 to the second input port A of the second shuttle valve 43. When the switching valve 42 is in the second position, the second input port A of the second shuttle valve 43 is connected to the oil tank 1. At this time, the pressure at the second output port B is always greater than that at the second input port A, thus enabling the LS port of the priority valve 22 to connect to the control port of the pressure compensation valve 211.

[0051] The output flow rate of the load-sensitive variable pump 21 depends on the magnitude of the pressure signal input from the interaction module 4 to the control port of the pressure compensation valve 211. The pressure signal cannot visually indicate the swashplate angle of the load-sensitive variable pump 21, thus making it impossible to determine the output flow rate. Therefore, optionally, the steering module 2 also includes a displacement sensor capable of monitoring the swashplate angle of the load-sensitive variable pump 21. In this embodiment, the steering module 2 has a built-in displacement sensor that can measure the swashplate angle of the load-sensitive variable pump 21, thereby determining the displacement of the load-sensitive variable pump 21. Then, by acquiring the engine speed, the output flow rate of the load-sensitive variable pump 21 can be calculated.

[0052] Optionally, the execution module 3 further includes a pressure sensor 35, which is used to monitor the oil pressure at the pressure port of the front-end valve 311. In this embodiment, the function of the pressure sensor 35 is to monitor the oil pressure at the pressure port of the front-end valve 311, thereby controlling the swashplate angle of the positive flow variable pump 34 and the state of the switching valve 42.

[0053] Optionally, the execution module 3 further includes a pilot valve assembly 36, the working ports of which are connected to the pilot ends of the positive flow variable pump 34 and the positive flow multi-way valve assembly 31, respectively. In this embodiment, the function of the pilot valve assembly 36 is to provide an oil source to the pilot end of the positive flow multi-way valve assembly 31, and at the same time provide a standby pressure to the positive flow variable pump 34 (the swashplate of the plunger variable pump cannot be completely reduced to 0, otherwise the pump swashplate cannot be started).

[0054] Optionally, the execution module 3 further includes a pilot pump 37, the inlet of which is connected to the oil tank 1, and the outlet of which is connected to the inlet of the pilot valve assembly 36. In this embodiment, the pilot pump 37 provides a high-pressure oil source for the pilot valve assembly 36.

[0055] In other embodiments, pilot pump 37 may optionally be omitted, in which case the oil inlet of pilot valve assembly 36 needs to be connected to other high-pressure oil sources.

[0056] Optionally, the pilot valve assembly 36 may include a pilot pipe 361, a proportional relief valve 362, a first check valve 363, and an accumulator 364. One end of the pilot pipe 361 is connected to the pilot pump 37, and the other end of the pilot pipe 361 is connected to the oil supply port of the positive flow variable pump 34 and the pilot end of the positive flow multi-way valve assembly 31, respectively. The first check valve 363 is connected in series with the pilot pipe 361 and allows the oil in the pilot pipe 361 to flow from one end to the other. One end of the proportional relief valve 362 is connected to the pilot pipe 361, and the other end is connected to the oil tank 1. The accumulator 364 is connected to the pilot pipe 361. The proportional relief valve 362 and the accumulator 364 are located on both sides of the first check valve 363, respectively. In this embodiment, the high-pressure oil generated by the pilot pump 37 flows from one end of the pilot tube 361 to the other. During this process, the accumulator 364 stores the high-pressure oil, thereby providing a stable pilot oil source for the oil supply port of the positive flow variable pump 34 and the pilot end of the positive flow multi-way valve group 31. The proportional relief valve 362 is used to regulate the oil pressure in the pilot tube 361, stabilizing the oil pressure in the pilot tube 361 at a preset value regulated by the proportional relief valve 362. The first check valve 363 prevents the oil in the accumulator 364 from flowing to one end of the pilot tube 361.

[0057] In other embodiments, the proportional relief valve 362 may optionally be omitted from the pilot valve assembly 36.

[0058] Optionally, the pilot valve assembly 36 further includes a filter 365 and a second check valve 366. The filter 365 is connected in series in the pilot tube 361 and located between the pilot pump 37 and the proportional relief valve 362. The second check valve 366 is connected in parallel with the filter 365, allowing oil from the end of the filter 365 near the pilot pump 37 to flow towards the end of the filter 365 near the proportional relief valve 362. In this embodiment, the filter 365 can filter the high-pressure oil supplied by the pilot pump 37 to prevent impurities in the high-pressure oil in the pilot tube 361. When the oil pressure at the end of the filter 365 near the pilot pump 37 is greater than the through pressure set by the second check valve 366, the second check valve 366 allows oil from the end of the filter 365 near the pilot pump 37 to flow towards the end of the filter 365 near the proportional relief valve 362, thereby preventing excessive oil pressure in the pilot tube 361 between the filter 365 and the pilot pump 37.

[0059] As the filter 365 operates for an extended period, impurities gradually accumulate within it, leading to a gradual increase in oil pressure at the end of the filter 365 closest to the pilot pump 37. When the impurities in the filter 365 become so numerous that it cannot function properly, the second check valve 366 activates. Optionally, during normal operation of the filter 365, the oil pressure passing through the second check valve 366 is greater than the oil pressure at the end of the filter 365 closest to the pilot pump 37.

[0060] Optionally, the front valve 311 and the rear valve 312 are connected in series. The T port of the front valve 311 is connected to the P port of the rear valve 312.

[0061] Optionally, the positive flow multi-way valve assembly 31 further includes a front-end pilot valve a313, a front-end pilot valve b314, a rear-end pilot valve a315, and a rear-end pilot valve b316. Front-end pilot valves a313 and b314 are respectively connected to the pilot ports at both ends of the front-end valve 311, and rear-end pilot valves a315 and b316 are respectively connected to the pilot ports at both ends of the rear-end valve 312. The inlet ports of pilot valves A313, B314, A315, and B316 are connected to the other end of pilot tube 361. The return ports of pilot valves A313, B314, A315, and B316 are connected to oil tank 1. By controlling pilot valves A313 and B314, the movement position of the valve core of pilot valve 311 can be controlled. By controlling pilot valves A315 and B316, the movement position of the valve core of pilot valve 312 can be controlled.

[0062] Optionally, the front pilot valve a313, the front pilot valve b314, the rear pilot valve a315, and the rear pilot valve b316 are all two-position three-way solenoid valves.

[0063] Optionally, the positive flow variable pump 34 is an electronically controlled positive flow variable pump. In this embodiment, the displacement of the electronically controlled positive flow variable pump is controlled by current to adjust the swashplate opening, thereby achieving precise displacement output. The output flow rate of the electronically controlled positive flow pump can be obtained by collecting the engine speed.

[0064] This embodiment also provides a loader, including the dual-pump confluence system described above.

[0065] When the loader turns, the steering pump of the steering module 2 is a load-sensitive variable pump 21, which will automatically adjust the displacement of the load-sensitive variable pump 21 according to the flow required by the steering module 2, so as not to generate excess flow and achieve energy saving.

[0066] Execution module 3 is an electronically controlled positive flow variable pump. When execution module 3 is under micro-control (precise control of lifting, lowering, bucket closing, and unloading), the electronically controlled positive flow variable pump supplies oil independently. Interaction module 4 is in the second mode, and steering module 2 does not participate in the operation.

[0067] When the execution module 3 needs to work quickly (the boom cylinder 32 and / or the bucket cylinder 33 extend and retract quickly), the interaction module 4 is in the first mode. Among the three points—the inlet of the boom cylinder 32, the inlet of the bucket cylinder 33, and the LS interface of the priority valve 22—the one with the highest oil pressure is selected and connected to the control port of the pressure compensation valve 211 of the load-sensitive variable pump 21. The high-pressure signal is transmitted to the load-sensitive variable pump 21. When the load-sensitive variable pump 21 receives the high-pressure signal, it will change its displacement, increase the pump flow, and thus supply oil from the load-sensitive variable pump 21 to the execution module 3.

[0068] Because of the participation of the interaction module 4, the dual-pump confluence system can cut off or connect the pressure signal of the load-sensitive variable pump 21 at any time, thereby determining whether the load-sensitive variable pump 21 participates in the fuel supply process of the execution module 3. For example, when the engine is idling, the execution module 3 performs lifting or bucket retraction to build up pressure (lifting to the top or retracting to the top, and maintaining this state, the positive flow multi-way valve group 31 is still at its maximum opening, because the positive flow variable pump will continue to supply fuel at a large displacement until the system pressure rises to the system pressure, at which point the positive flow variable pump displacement will decrease to its minimum). If the engine power is insufficient, it may cause the engine to stall due to pressure buildup. At this time, the load-sensitive variable pump 21 can be stopped from supplying fuel to the execution module 3, allowing only the positive flow variable pump to be in a pressure buildup state, which can solve this problem.

[0069] For example, in order to reduce the maximum power torque of the engine, the two pumps can be combined at low pressure and high flow. When the dual pump combined system reaches a certain pressure, the load-sensitive variable pump 21 stops supplying oil to the execution module 3, and the positive flow variable pump supplies oil separately to meet the maximum power requirements of the engine, so that it is not necessary to use a very high power engine.

[0070] When the interaction module 4 is in the first mode, and the valve core of the positive flow multi-way valve group 31 is at a certain opening degree, the required flow rate of the execution module 3 has been determined. This system can calculate the output flow rate of the load-sensitive variable pump 21, thereby obtaining the flow rate required by the electronically controlled positive flow variable pump. By controlling the control current of the electronically controlled positive flow variable pump and collecting the engine speed, the required flow rate of the electronically controlled positive flow variable pump can be precisely controlled.

[0071] To save energy, execution module 3 employs a positive flow system (the control signal for positive flow comes from the pilot secondary pressure). The principle is to select the highest secondary pressure signal to control the electronically controlled positive flow variable pump. When the handle displacement increases, the secondary pilot pressure rises, and this increased pressure signal acts on the electronically controlled positive flow variable pump, causing the swashplate angle to increase and the displacement to increase. Conversely, when the handle displacement decreases, the secondary pilot pressure decreases, and the displacement of the electronically controlled positive flow variable pump decreases, thus matching the flow rate of the electronically controlled positive flow variable pump with the flow rate requirements of execution module 3.

[0072] Optionally, the displacement of the handle corresponds to adjusting the state of the front pilot valve a313, the front pilot valve b314, the rear pilot valve a315, and the rear pilot valve b316.

[0073] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the implementation of the present invention. Those skilled in the art can make other variations or modifications based on the above description. It is neither necessary nor possible to exhaustively describe all embodiments here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the claims of the present invention.

Claims

1. A dual-pump confluence system, characterized in that, include: Fuel tank (1); The steering module (2) includes a load-sensitive variable pump (21) and a priority valve (22), and the oil tank (1), the load-sensitive variable pump (21) and the priority valve (22) are connected in sequence; The execution module (3) includes a positive flow multi-way valve group (31), at least two execution cylinders and a positive flow variable pump (34). The positive flow multi-way valve group (31) includes at least two multi-way valves. The at least two multi-way valves are connected to the at least two execution cylinders in a one-to-one correspondence to form a circulating fluid circuit. The pressure port of the positive flow multi-way valve group (31) is connected to the EF port of the priority valve (22). The oil outlet of the positive flow variable pump (34) is connected to the pressure port of the positive flow multi-way valve group (31). The interaction module (4) includes a first mode and a second mode. In the first mode, the load pressure of at least two of the actuator cylinders and the pressure at the LS interface of the priority valve (22) are selected, and the one with the highest oil pressure is connected to the control port of the pressure compensation valve (211) of the load-sensitive variable pump (21). In the second mode, the LS interface of the priority valve (22) is connected to the control port of the pressure compensation valve (211).

2. The dual-pump confluence system according to claim 1, characterized in that, The actuator is provided with two cylinders, namely a boom cylinder (32) and a bucket cylinder (33); The positive flow multi-way valve group (31) includes two multi-way valves, namely a front valve (311) and a rear valve (312). The front valve (311) and the bucket cylinder (33) are connected to form a circulating fluid circuit, and the rear valve (312) and the boom cylinder (32) are connected to form a circulating fluid circuit. The front valve (311) and the rear valve (312) are connected in series. The pressure port of the front valve (311) is connected to the EF port of the priority valve (22), and the outlet of the positive flow variable pump (34) is connected to the pressure port of the front valve (311). In the first mode, the interaction module (4) selects the one with the highest oil pressure among the three locations: the inlet of the boom cylinder (32), the inlet of the bucket cylinder (33), and the LS interface of the priority valve (22), and connects it to the control port of the pressure compensation valve (211) of the load-sensitive variable pump (21).

3. The dual-pump confluence system according to claim 2, characterized in that, The interactive module (4) includes a first shuttle valve (41), a switching valve (42), and a second shuttle valve (43). The first input port A and the first input port B of the first shuttle valve (41) are connected to the inlet of the boom cylinder (32) and the inlet of the bucket cylinder (33), respectively. The first output port of the first shuttle valve (41) is connected to the inlet of the switching valve (42). The second input port A and the second input port B of the second shuttle valve (43) are respectively connected to the outlet of the switching valve (42) and the LS interface of the priority valve (22), and the second output port of the second shuttle valve (43) is connected to the control port of the pressure compensation valve (211).

4. The dual-pump confluence system according to claim 3, characterized in that, The switching valve (42) is a two-position three-way valve. The first port of the switching valve (42) is connected to the first output port, the second port of the switching valve (42) is connected to the second input port A of the second shuttle valve (43), and the third port of the switching valve (42) is connected to the oil tank (1). The switching valve (42) includes a first position and a second position. In the first position, the first port and the second port are connected. In the second position, the second port and the third port are connected.

5. The dual-pump confluence system according to claim 1, characterized in that, The steering module (2) also includes a displacement sensor that can monitor the swashplate tilt angle of the load-sensitive variable pump (21).

6. The dual-pump confluence system according to claim 1, characterized in that, The execution module (3) also includes a pressure sensor (35), which is used to monitor the oil pressure at the pressure port of the positive flow multi-way valve group (31).

7. The dual-pump confluence system according to claim 1, characterized in that, The execution module (3) also includes a pilot valve group (36), the working port of which is connected to the pilot end of the positive flow variable pump (34) and the positive flow multi-way valve group (31).

8. The dual-pump confluence system according to claim 7, characterized in that, The execution module (3) further includes a pilot pump (37), the inlet of which is connected to the oil tank (1), and the outlet of which is connected to the inlet of the pilot valve group (36).

9. The dual-pump confluence system according to claim 8, characterized in that, The pilot valve assembly (36) includes a pilot tube (361), a proportional relief valve (362), a first check valve (363), and an accumulator (364). One end of the pilot tube (361) is connected to the pilot pump (37), and the other end of the pilot tube (361) is connected to the oil supply port of the positive flow variable pump (34) and the pilot end of the positive flow multi-way valve assembly (31), respectively. The first check valve (363) is connected in series with the pilot tube (361) and allows the oil in the pilot tube (361) to flow from one end to the other end. One end of the proportional relief valve (362) is connected to the pilot tube (361), and the other end is connected to the oil tank (1). The accumulator (364) is connected to the pilot tube (361). The proportional relief valve (362) and the accumulator (364) are located on both sides of the first check valve (363), respectively.

10. A loader, characterized in that, Includes the dual-pump confluence system as described in any one of claims 1-9.

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