Double-pump confluence system and loader

Abstract

The invention relates to the technical field of engineering machinery, and particularly discloses a double-pump confluence system and a loader, the double-pump confluence system comprises an oil tank, a steering module, an execution module and an interaction module, and when the loader provided with the double-pump confluence system works and the interaction module is switched to a second mode, the interaction module is switched to the second mode; the steering module and the execution module respectively control respective displacement, so that the steering module and the execution module respectively meet respective pressure oil consumption; when the interaction module is switched to the first mode, signal interaction can be achieved between the steering module and the execution module, then the displacement of the load-sensitive variable pump and the displacement of the positive flow variable pump can be controlled, the problem of insufficient flow or redundant flow in the system is avoided, and the energy-saving effect is improved. Meanwhile, the steering module adopts a load-sensitive system and has the characteristic of high safety, and the execution module adopts a positive flow system, so that the energy-saving effect is realized.

Description

Technical Field

[0001] The present invention relates to the technical field of engineering machinery, and in particular to a dual-pump confluence system and a loader. Background Art

[0002] Loaders are essential equipment in construction, primarily used for shoveling, loading, transporting, and excavating loose materials. To save energy, loader hydraulic systems typically utilize a dual-pump confluence system, which reduces hydraulic component costs and facilitates component layout design.

[0003] Existing loader hydraulic systems generally employ the following systems: 1. The fixed-displacement pump merging system. This system has the advantage of utilizing the steering pump's flow rate to simultaneously supply the working system. However, its disadvantage is that when the system is idle, the fixed-displacement pump's speed continues to output flow in line with engine rotation, preventing the pump from adjusting its displacement, resulting in energy losses. 2. The steering single-variable merging system (steering load-sensing system, fixed-displacement pump for the working system). This system has the advantage of utilizing a variable displacement pump for the steering pump. This prevents excess flow during fast, slow, or no steering, thus saving energy. This system also utilizes the steering pump's flow rate to simultaneously supply the working system. However, its disadvantage is that when the system is idle, the fixed-displacement pump's speed continues to output flow in line with engine rotation, preventing the pump from adjusting its displacement, resulting in energy losses. 3. The dual-variable load-sensing merging system. This system has the advantage of enabling dual pumps to meet system demand at any time, providing on-demand flow and saving energy. However, this system suffers from ΔP losses, and as loaders grow in size, the required system flow (and pump displacement) increases, increasing power losses. 4. The electronically controlled positive flow system based on the electric steering system (the steering system adopts the electronic control system, and the working system adopts the positive flow system) has the advantage of no △P loss, thus achieving energy saving. The disadvantage is that the steering system adopts electronic steering. If the electronic control fails, the steering will fail, posing a safety hazard (for engineering machinery, steering must be given priority to ensure safety). 5. The positive flow hydraulic system based on the load-sensitive electronically controlled pump has the advantage that the steering system adopts a load-sensitive system for high safety, and the working system adopts a positive flow system for energy saving. The disadvantage is that the electronically controlled steering pump and the working system have no interaction and cannot sense the required flow of the working system. There may be problems of insufficient flow or excess flow, which in turn cannot effectively achieve energy saving effects. In the above-mentioned dual-pump confluence system, energy saving and reliability cannot be achieved at the same time.

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

[0005] The object of the present invention is to provide a dual-pump merging system and a loader to solve the problem in the related art that energy saving and high reliability cannot be achieved simultaneously in the existing dual-pump merging system.

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

[0007] tank;

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

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

[0010] The interactive module 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 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, there are two actuator cylinders, one for the boom and the other for the bucket.

[0012] The positive flow multi-way valve group includes two multi-way valves, the two multi-way valves are respectively a front valve and a rear valve, the front valve and the bucket cylinder are connected to form a circulating fluid circuit, 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 oil port of the front valve is communicated with the EF port of the priority valve, and the oil outlet of the positive flow variable pump is communicated with the pressure oil port of the front valve;

[0013] In the first mode, the interactive 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 to connect with the control port of the pressure compensation valve of the load-sensing variable pump.

[0014] As a preferred technical solution for the dual-pump confluence system, the interaction module includes a first shuttle valve, an on-off 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. The first output port of the first shuttle valve is connected to the inlet of the on-off 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 switch 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 merging system, the switch valve is a two-position three-way valve, the first interface of the switch valve is connected to the first output port, the second interface of the switch valve is connected to the second input A port of the second shuttle valve, and the third interface of the switch valve is connected to the oil tank. The switch valve includes a first position and a second position. In the first position, the first interface is connected to the second interface, and in the second position, the second interface is connected to the third interface.

[0017] As a preferred technical solution of the dual-pump merging system, the steering module further includes a displacement sensor, which can monitor the inclination angle of the swash plate of the load-sensing variable displacement pump.

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

[0019] As an optimal technical solution for the dual-pump confluence system, the execution module further includes a pilot valve group, the working oil ports of the pilot valve group are respectively connected to the pilot ends of the positive flow variable pump and the positive flow multi-way valve group.

[0020] As an optimal technical solution for the dual-pump merging system, the execution module further includes a pilot pump, the oil inlet of the pilot pump is connected to the oil tank, and the oil outlet of the pilot pump is connected to the oil inlet of the pilot valve group.

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

[0022] As an optimal technical solution for the dual-pump merging system, the front-connected valve and the rear-connected valve are connected in series.

[0023] On the other hand, the present invention provides a loader comprising the dual-pump merging system of any of the above schemes.

[0024] The beneficial effects of the present invention are:

[0025] The present invention provides a dual-pump merging system and a loader, the dual-pump merging system includes a fuel tank, a steering module, an execution module and an interaction module, the steering module includes a load-sensitive variable pump and a priority valve, the fuel tank, the load-sensitive variable pump and the priority valve are connected in sequence; 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, at least two multi-way valves are connected to at least two execution cylinders in a one-to-one correspondence to form a circulating fluid path, the pressure oil 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 oil 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 load pressure of at least two of the execution cylinders and the pressure at the LS interface of the priority valve, the one with the highest oil pressure is selected and 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 module and execution module to operate independently. Switching the interaction module to the first mode allows signal exchange between the steering and execution modules, enabling control of the displacement of the load-sensing variable pump and the positive-flow variable pump, avoiding insufficient or excessive flow in the system and improving energy efficiency. Furthermore, the steering module utilizes a load-sensing system for enhanced safety, while the execution module utilizes a positive-flow system for energy efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 The liquid circuit of the dual pump confluence system in the embodiment of the present invention Figure 1 ;

[0027] Figure 2 The liquid circuit of the dual pump confluence system in the embodiment of the present invention Figure 2 .

[0028] In the picture:

[0029] 1. Fuel tank;

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

[0031] 3. Actuator module; 31. Positive flow multi-way valve group; 311. Front-link valve; 312. Rear-link valve; 313. Front-link pilot valve a; 314. Front-link pilot valve b; 315. Rear-link pilot valve a; 316. Rear-link pilot valve b; 32. Boom cylinder; 33. Bucket cylinder; 34. Positive flow variable pump; 35. Pressure sensor; 36. Pilot valve group; 361. Pilot pipe; 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 DESCRIPTION

[0033] The technical solution of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0034] In the description of the present invention, it should be noted that the terms "center", "up", "down", "left", "right", "vertical", "horizontal", "inside", "outside" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and are not intended to indicate or imply that the devices or elements referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention. In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance. Among them, the terms "first position" and "second position" are two different positions, and the first feature being "above", "above" and "above" the second feature includes the first feature being directly above and obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. The first feature being "below", "below" and "below" the second feature includes the first feature being directly below and obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0035] In the description of the present invention, it should be noted that, unless otherwise expressly specified or limited, the terms "mounted," "connected," and "connected" should be understood in a broad sense. For example, they may refer to fixed, detachable, or integral connections; mechanical or electrical connections; direct or indirect connections through an intermediate medium; and internal communication between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on the specific circumstances.

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

[0037] like Figures 1 and 2 As shown, this embodiment provides a dual-pump confluence system, which includes a fuel 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 fuel 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 path. The pressure oil port of the positive flow multi-way valve group 31 is connected to the priority valve. The EF port of the valve 22 is connected, and the oil outlet of the positive flow variable pump 34 is connected to the pressure oil port of the positive flow multi-way valve group 31; the interactive module 4 includes a first mode and a second mode. In the first mode, the load pressure of at least two execution cylinders and the pressure at the LS interface of the priority valve 22, that is, the oil pressure at the oil inlet of the execution cylinder and the oil pressure at the LS interface of the priority valve 22, select the one with the highest oil pressure to be connected to the control port of the pressure compensation valve 211 of the load sensitive variable pump 21, and in the second mode, the LS interface of the priority valve 22 is connected to the control port of the pressure compensation valve 211.

[0038] When the loader equipped with the dual-pump confluence system is working, when the interaction module 4 is switched to the second mode, the steering module 2 and the execution module 3 work independently of each other. At this time, the steering module 2 and the execution module 3 each control their own displacement so that the steering module 2 and the execution module 3 each meet their own pressure oil consumption;

[0039] When the interactive module 4 is switched to the first mode, signal interaction can be achieved between the steering module 2 and the execution module 3. At least two execution cylinders and the LS interface of the priority valve 22 are connected 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 for 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 for the steering module 2.

[0040] Optionally, the steering module 2 adopts a load-sensitive system with high safety, and the execution module 3 adopts a positive flow system to achieve energy-saving effects.

[0041] Optionally, the steering module 2 further 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 between the load-sensing variable displacement pump 21, the priority valve 22, the steering gear 23, and the steering cylinder 24 is conventional and will not be described in detail here.

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

[0043] Optionally, the steering module 2 may be a flow amplification system provided with a load-sensing variable displacement pump 21 .

[0044] When the interactive module 4 is in the first mode, the interactive module 4 first selects the inlets of two actuator cylinders out of at least two actuator cylinders for comparison, selects the largest one for comparison with the inlets of other actuator cylinders that have not been compared, until the maximum actuator cylinder inlet pressure is compared, and then compares the pressure with the pressure value at the LS interface of the priority valve 22, and finally transmits the signal with the largest pressure to the control port of the pressure compensation valve 211.

[0045] Optionally, the execution cylinder includes a boom cylinder 32 and a bucket cylinder 33; the positive flow multi-way valve group 31 includes two multi-way valves, the two multi-way valves are 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, 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 oil port of the front valve 311 is connected to the EF port of the priority valve 22, and the oil outlet of the positive flow variable pump 34 is connected to the pressure oil port of the front valve 311; in the first mode of the interactive module 4, 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 is selected to be connected to the control port of the pressure compensation valve 211 of the load-sensitive variable pump 21. In this embodiment, there are two execution cylinders, namely the boom cylinder 32 and the bucket cylinder 33. In the first mode, the interactive module 4 first selects the one with the largest pressure value at the pressure oil port of the boom cylinder 32 and the bucket cylinder 33, and then compares the pressure value with the pressure value at the LS interface of the priority valve 22 to select the one with the largest pressure among the three to connect to the control port of the pressure compensation valve 211 of the load-sensing variable pump 21.

[0046] In this embodiment, the positive flow multi-way valve group 31 includes two multi-way valves, which are 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] Regarding the specific structure of the interactive module 4, optionally, the interactive module 4 includes a first shuttle valve 41, a switch valve 42 and a second shuttle valve 43. The first input A port and the first input B port of the first shuttle valve 41 are respectively connected to the inlet of the boom cylinder 32 and the inlet of the bucket cylinder 33, and the first output port of the first shuttle valve 41 is connected to the inlet of the switch valve 42; the second input A port and the second input B port of the second shuttle valve 43 are respectively connected to the outlet of the switch 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. In this embodiment, when in the first mode, the switch valve 42 connects the first output port and the second input port A. At this time, the pressure oil in the inlet of the boom cylinder 32 and the inlet of the bucket cylinder 33 flow 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, and connects the inlet of the boom cylinder 32 and the inlet of the bucket cylinder 33 with the second input port A of the second shuttle valve 43. Then, the second shuttle valve 43 compares the oil pressures of the second input port A and the second input port B, and then connects the pressure with the larger pressure value to the control port of the pressure compensation valve 211, so as to realize that 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 is selected as the pressure signal to be connected to the control port of the pressure compensation valve 211 of the load sensing variable pump 21, and then controls the valve core of the pressure compensation valve 211 to adjust the inclination angle of the swash plate of the load sensing variable pump 21.

[0049] In other embodiments, optionally, when the execution cylinders are set to three or more, the number of shuttle valves in the interaction module 4 is correspondingly set to three or more, so that the pressure values can be compared at the LS interfaces of three or more execution cylinders and the priority valve 22.

[0050] Regarding the specific structure of the on-off valve 42, the on-off valve 42 can optionally be a two-position, three-way valve. The first port of the on-off valve 42 is connected to the first output port, the second port of the on-off valve 42 is connected to the second input port A of the second shuttle valve 43, and the third port of the on-off valve 42 is connected to the fuel tank 1. The on-off valve 42 includes a first position and a second position. In the first position, the first port and the second port are connected, and in the second position, the second port and the third port are connected. In this embodiment, the on-off valve 42 is adjusted between the first position and the second position by moving the valve core. When the on-off valve 42 is in the first position, the first port and the second port 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 on-off valve 42 is in the second position, the second input port A of the second shuttle valve 43 is connected to the fuel tank 1. At this time, the pressure at the second output port B is always greater than that at the second input port A, thereby connecting the LS port of the priority valve 22 to the control port of the pressure compensation valve 211.

[0051] The output flow of the load-sensing 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 intuitively display the swash plate angle position of the load-sensing variable pump 21, and thus cannot determine the output flow of the load-sensing variable pump 21. To this end, the steering module 2 optionally also includes a displacement sensor capable of monitoring the swash plate angle of the load-sensing variable pump 21. In this embodiment, the steering module 2 includes a built-in displacement sensor that can measure the swash plate angle of the load-sensing variable pump 21, thereby deriving the displacement of the load-sensing variable pump 21. The output flow of the load-sensing variable pump 21 can then be calculated by collecting the engine speed.

[0052] Optionally, the execution module 3 further includes a pressure sensor 35 for monitoring the oil pressure at the pressure port of the front coupling valve 311. In this embodiment, the pressure sensor 35 monitors the oil pressure at the pressure port of the front coupling valve 311 to control the swash plate angle of the positive flow variable pump 34 and the state of the on-off valve 42.

[0053] Optionally, actuator module 3 further includes a pilot valve assembly 36, whose operating oil ports are connected to the pilot end of positive flow variable pump 34 and positive flow multi-way valve assembly 31. In this embodiment, pilot valve assembly 36 provides an oil source to the pilot end of positive flow multi-way valve assembly 31 and a standby pressure to positive flow variable pump 34 (the swash plate of the plunger variable pump cannot be completely reduced to zero, otherwise the pump swash plate cannot be activated).

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

[0055] In other embodiments, optionally, the pilot pump 37 may also be eliminated, in which case the oil inlet of the pilot valve group 36 needs to be connected to another high-pressure oil source.

[0056] As for the specific structure of the pilot valve group 36, optionally, the pilot valve group 36 includes a pilot pipe 361, a proportional relief valve 362, a first one-way 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 respectively connected to 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 first one-way valve 363 is connected in series to the pilot pipe 361, and the first one-way valve 363 allows the oil in the pilot pipe 361 to flow from one end to the other end, 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, and the proportional relief valve 362 and the accumulator 364 are respectively located on both sides of the first one-way valve 363. In this embodiment, the high-pressure oil generated by the pilot pump 37 flows from one end of the pilot line 361 to the other. During this process, the accumulator 364 is used to store the high-pressure oil, thereby providing a stable pressure source of pilot oil 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. The proportional relief valve 362 is used to regulate the oil pressure in the pilot line 361, stabilizing it at a preset value set by the proportional relief valve 362. The first check valve 363 prevents the oil in the accumulator 364 from flowing toward one end of the pilot line 361.

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

[0058] Optionally, the pilot valve assembly 36 also includes a filter 365 and a second one-way valve 366. The filter 365 is connected in series with the pilot line 361 and is located between the pilot pump 37 and the proportional relief valve 362. The second one-way valve 366 is connected in parallel with the filter 365. The second one-way valve 366 allows oil from the end of the filter 365 near the pilot pump 37 to flow toward the end of the filter 365 near the proportional relief valve 362. In this embodiment, the filter 365 filters the high-pressure oil supplied by the pilot pump 37 to prevent impurities from entering the high-pressure oil in the pilot line 361. When the oil pressure at the end of the filter 365 near the pilot pump 37 exceeds the set pressure of the second one-way valve 366, the second one-way valve 366 allows the oil from the end of the filter 365 near the pilot pump 37 to flow toward the end of the filter 365 near the proportional relief valve 362, thereby preventing excessive oil pressure in the pilot line 361 between the filter 365 and the pilot pump 37.

[0059] As filter 365 operates for an extended period of time, impurities gradually accumulate within filter 365, causing the oil pressure at the end of filter 365 near pilot pump 37 to gradually increase. When impurities accumulate to the point where filter 365 cannot function properly, second one-way valve 366 is opened. Alternatively, when filter 365 is functioning properly, the oil pressure passing through second one-way valve 366 is greater than the oil pressure at the end of filter 365 near pilot pump 37.

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

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

[0062] Optionally, the front-link pilot valve a313 , the front-link pilot valve b314 , the rear-link pilot valve a315 and the rear-link 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 through the swash plate opening, thereby achieving precise displacement output. The output flow of the electronically controlled positive flow pump can be obtained by collecting engine speed.

[0064] This embodiment also provides a loader, including the dual-pump merging system in the above solution.

[0065] When the loader turns, the steering pump of the steering module 2 is a load-sensitive variable displacement pump 21 , which automatically adjusts the displacement of the load-sensitive variable displacement pump 21 according to the flow required by the steering module 2 , without generating excess flow, thereby achieving energy saving.

[0066] Execution Module 3 is an electronically controlled positive flow variable pump. When Execution Module 3 is performing micro-control (for precise control of lifting, lowering, bucket retraction, and unloading), the electronically controlled positive flow variable pump independently supplies oil. Interaction Module 4 is in the second mode, and Steering Module 2 is not involved.

[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, and among 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 to be connected to the control port of the pressure compensation valve 211 of the load-sensitive variable pump 21, and 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, the displacement of the load-sensitive variable pump 21 changes, the pump flow rate is increased, and the oil of the load-sensitive variable pump 21 is supplied to the execution module 3.

[0068] Because of the participation of the interactive 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 oil supply process of the execution module 3. For example, when the engine is idling, the execution module 3 lifts or retracts the bucket to hold the pressure (lifts to the top or retracts the bucket to the top, and continues to maintain this state. The positive flow multi-way valve group 31 is still at the maximum opening, because the displacement of the positive flow variable pump will still be supplied at a large displacement until the system pressure rises to the system pressure, and the displacement of the positive flow variable pump is reduced to the minimum). If the engine power is insufficient, it will cause the pressure to be held and the engine to stall. At this time, the load-sensitive variable pump 21 can be stopped from supplying oil to the execution module 3, and only the positive flow variable pump can be allowed to hold the pressure, which can solve this problem.

[0069] For another example, in order to reduce the maximum power torque of the engine, the two pumps can be merged at low pressure and high flow. When the dual pump merging system reaches a certain pressure, the load-sensitive variable pump 21 is stopped from supplying oil to the execution module 3, and the positive flow variable pump is allowed to supply oil alone to meet the maximum power requirement of the engine, etc., so there is no need to use a very high-power engine, etc.

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

[0071] To conserve energy, actuator module 3 employs a positive flow system (the positive flow control signal is derived from the pilot secondary pressure). This system selects the highest secondary pressure signal to control the electronically controlled positive flow variable pump. As the handle displacement increases, the secondary pilot pressure rises. This increased pressure signal acts on the electronically controlled positive flow variable pump, increasing the pump's swash plate angle and displacement. Conversely, as the handle displacement decreases, the secondary pilot pressure decreases, reducing the pump's displacement. This ensures that the pump's flow rate matches the flow requirements of actuator module 3.

[0072] Optionally, the displacement of the handle is equivalent to adjusting the states of the front-link pilot valve a313, the front-link pilot valve b314, the rear-link pilot valve a315 and the rear-link pilot valve b316.

[0073] Obviously, the above embodiments of the present invention are merely examples for the purpose of clearly illustrating the present invention, and are not intended to limit the embodiments of the present invention. Those skilled in the art will appreciate that other variations or modifications can be made based on the above description. It is not necessary and impossible to enumerate all embodiments here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention shall be included within the scope of protection of the claims of the present invention.

Claims

1. Double pump confluence system, characterized in that: include: Fuel tank (1); The steering module (2) comprises a load-sensitive variable displacement pump (21) and a priority valve (22), wherein the oil tank (1), the load-sensitive variable displacement pump (21) and the priority valve (22) are connected in sequence; An execution module (3) comprises a positive flow multi-way valve group (31), at least two execution oil cylinders and a positive flow variable pump (34), wherein the positive flow multi-way valve group (31) comprises at least two multi-way valves, at least two of the multi-way valves are connected to at least two of the execution oil cylinders in a one-to-one correspondence to form a circulating fluid path, the pressure oil port of the positive flow multi-way valve group (31) is communicated with the EF port of the priority valve (22), and the oil outlet of the positive flow variable pump (34) is communicated with the pressure oil port of the positive flow multi-way valve group (31); The interactive module (4) includes a first mode and a second mode. In the first mode, the load pressures 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-sensing 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 execution cylinders are provided with two, namely a boom cylinder (32) and a bucket cylinder (33); The positive flow multi-way valve group (31) includes two multi-way valves, the two multi-way valves are respectively a front valve (311) and a rear valve (312), the front valve (311) and the bucket oil cylinder (33) are connected to form a circulating fluid circuit, the rear valve (312) and the boom oil 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 oil port of the front valve (311) is communicated with the EF port of the priority valve (22), and the oil outlet of the positive flow variable pump (34) is communicated with the pressure oil 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) to communicate with the control port of the pressure compensation valve (211) of the load-sensing variable pump (21).

3. The dual pump confluence system according to claim 2, characterized in that: The interactive module (4) comprises a first shuttle valve (41), an on-off valve (42) and a second shuttle valve (43); a first input port A and a first input port B of the first shuttle valve (41) are respectively connected to the inlet of the boom cylinder (32) and the inlet of the bucket cylinder (33); and a first output port of the first shuttle valve (41) is connected to the inlet of the on-off 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 switch 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 switch valve (42) is a two-position three-way valve. The first interface of the switch valve (42) is connected to the first output port, the second interface of the switch valve (42) is connected to the second input port A of the second shuttle valve (43), and the third interface of the switch valve (42) is connected to the oil tank (1). The switch valve (42) includes a first position and a second position. In the first position, the first interface is connected to the second interface, and in the second position, the second interface is connected to the third interface.

5. The dual pump confluence system according to claim 1, characterized in that: The steering module (2) further comprises a displacement sensor capable of monitoring the swash plate inclination angle of the load-sensing variable displacement pump (21).

6. The dual pump confluence system according to claim 1, characterized in that: The execution module (3) further comprises a pressure sensor (35), and the pressure sensor (35) is used to monitor the oil pressure of the pressure oil 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) further comprises a pilot valve group (36), wherein the working oil port of the pilot valve group (36) is respectively 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 comprises a pilot pump (37), the oil inlet of the pilot pump (37) being in communication with the oil tank (1), and the oil outlet of the pilot pump (37) being in communication with the oil inlet of the pilot valve group (36).

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

10. A loader, characterized in that The invention comprises the dual-pump confluence system according to any one of claims 1 to 9.

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