Hydraulic control system and electric loader

Abstract

The present application belongs to the technical field of engineering machinery, and provides a hydraulic control system and an electric loader. Two groups of power sources, i.e., a first pump driving unit and a second pump driving unit, are arranged. In a low-flow working condition, a split-flow valve is in a right position in a power-off state, a low-pressure unloading of the second pump driving unit is realized, energy consumption in an empty state is significantly reduced, and a priority valve guarantees that the first pump driving unit provides accurate low-flow supply to a boom control unit and a bucket control unit, thereby improving energy utilization. In a high-flow working condition, the split-flow valve is in a left position in a power-on state, two pumps are in a high-pressure split-flow state, and large flow is output, thereby meeting the requirements of powerful operations such as boom lifting and bucket digging. In this way, through valve position switching, a flexible mode of "one-pump energy saving and two-pump large-flow adaptation" is realized, energy loss caused by throttling of a distribution valve is avoided, response speed and working efficiency in heavy loading are guaranteed, energy consumption of the loader is further reduced, and control flexibility is improved.

Description

Technical Field

[0001] This invention belongs to the field of engineering machinery technology, specifically relating to a hydraulic control system and an electric loader. Background Technology

[0002] Electric loaders, as an important piece of equipment in the construction machinery field, are electrically driven construction machinery mainly used for tasks such as material handling, loading and unloading, and site clearing. They are widely used in ports, mines, logistics, and construction. Compared with traditional fuel-powered loaders, electric loaders are purely electric-driven, resulting in significantly lower energy costs, and offer advantages such as zero emissions and low noise.

[0003] Existing loader steering pumps are typically configured with a fixed displacement or large displacement. During steering, the pump speed is controlled to idle to meet the loader's steering requirements. Therefore, a significant amount of oil passes through the priority valve during operation, resulting in relatively high energy consumption. When the loader is digging, unloading, lowering the boom, or performing micro-control operations, the required flow rate is smaller. Although the motor speed can be controlled via a handle signal, the pump flow rate remains high, necessitating throttling through a distribution valve. This generates heat and consumes electrical energy, directly impacting the equipment's economy and operational efficiency. Summary of the Invention

[0004] The purpose of this invention is to disclose a hydraulic control system that resolves the contradiction between energy waste under low flow conditions and insufficient oil supply under heavy load and high flow conditions in existing electric loaders, thereby solving the technical problem of high power consumption of the whole machine.

[0005] To achieve the above objectives, the present invention discloses a hydraulic control system, including a controller and connected thereto a distribution valve, a flow splitting and merging valve, a priority valve, a first pump drive unit, and a second pump drive unit, and also includes a steering gear, wherein the distribution valve includes a boom control unit and a bucket control unit; The oil outlet of the first pump drive unit is connected to the priority valve, and the oil outlet of the priority valve is connected to the oil inlet of the steering gear and one side of the oil inlet of the merging and splitting valve; the other side of the oil inlet of the merging and splitting valve is connected to the second pump drive unit, and the oil outlet is connected to the boom control unit and the bucket control unit. Under low flow conditions, the merging and splitting valve is de-energized and in the right position. The second pump drive unit is unloaded at low pressure and connected to the first pump drive unit through the priority valve, supplying a low flow to the boom control unit and / or the bucket control unit. Under high flow conditions, the merging and splitting valve is energized and in the left position. The first pump drive unit and the second pump drive unit are simultaneously connected to the high-pressure oil circuit and merged, supplying a high flow to the boom control unit and / or the bucket control unit.

[0006] This basic design employs two power sources: a first pump drive unit and a second pump drive unit. Under low-flow conditions, the merging and splitting valves are de-energized and in the right position, enabling low-pressure unloading of the second pump drive unit and significantly reducing no-load energy consumption. Simultaneously, the priority valve ensures the first pump drive unit provides precise low-flow power to the boom and bucket control units, improving energy utilization. Under high-flow conditions, the merging and splitting valves are energized and in the left position, executing high-pressure merging of the two pumps and outputting a large flow rate to meet the demands of heavy-duty operations such as boom lifting and bucket digging. Thus, by switching valve positions, a flexible mode of "one pump saving energy, two pumps adapting to large flow" is achieved, avoiding energy loss caused by throttling with the distribution valve, ensuring response speed and work efficiency under heavy loads, further reducing the loader's energy consumption and improving operational flexibility.

[0007] As an optional implementation, the flow splitting and merging valve includes a first pilot valve and a flow splitting and merging main valve; the control terminal of the first pilot valve is connected to the controller, and the oil outlet is connected to the control terminal of the flow splitting and merging main valve; the oil inlet P1 of the flow splitting and merging main valve is connected to the first pump drive unit, the oil inlet P2 is connected to the second pump drive unit, and the oil outlet is connected to the boom control unit and the bucket control unit. In response to the opening signal of the working handle, the controller drives the boom control unit and / or the bucket control unit to be turned on, so that the control end of the first pilot valve is de-energized, pushing the main valve of the flow divider and merge to the right position, and then the first pump drive unit is connected through the priority valve to output a low flow supply to the boom control unit and / or the bucket control unit. Alternatively, the control terminal of the first pilot valve can be energized and turned on, pushing the main valve of the flow splitting and merging to the left position, connecting the first pump drive unit and the second pump drive unit to the high-pressure oil circuit at the same time and achieving flow merging, so as to output a high flow supply to the boom control unit and / or the bucket control unit.

[0008] This solution employs a first pilot valve and a flow-diverting / merging main valve. The connection between the first pilot valve and the controller enables precise pilot control at low flow rates and logical coordination of flow-diverting at high flow rates, achieving energy efficiency management. The external flow-diverting / merging main valve allows for decision-making based on load requirements, avoiding complex merging channels within the main valve body, thus reducing pressure loss and heat generation, and facilitating future maintenance or replacement. Under low flow conditions, the flow-diverting / merging main valve operates in the right position, and the second pump drive unit is unloaded at low pressure, achieving high efficiency and energy saving under low flow conditions. Under high flow conditions, the flow-diverting / merging main valve operates in the left position, achieving high-pressure merging of the two pumps to meet peak power requirements, reducing standby energy consumption while ensuring rapid response and precise control during heavy-duty operations. Furthermore, the flow rate of a single or dual pump can be dynamically allocated to the boom or bucket according to operational needs, achieving coordinated merging of lifting and unloading actions, thereby improving the efficiency of combined actions and avoiding pressure competition.

[0009] As an optional implementation, the first pump drive unit includes a steering pump and a steering motor that are electrically connected; the oil inlet of the steering pump is connected to the oil tank, and the oil outlet is connected to the priority valve; the steering motor is connected to the controller. When the steering gear is triggered, it pushes the priority valve to the left position. Then, the oil inlet and outlet CF of the priority valve are connected, supplying oil to the steering gear and performing steering. Otherwise, if the priority valve is in the right position, the oil inlet and outlet EF of the priority valve are connected, connecting the steering pump and the flow divider / merge valve to perform small-flow loading and unloading operations.

[0010] This solution is equipped with a small-displacement steering pump and steering motor corresponding to the steering gear, which can realize independent control of the steering pump speed as needed; through the connection between the steering motor and the controller, the flow requirements of the micro-control section are met, thereby enabling precise adjustment of flow and pressure according to the actual load, significantly reducing energy loss under non-steering conditions, and avoiding energy loss caused by throttling of the distribution valve.

[0011] As an optional implementation, the second pump drive unit includes a working pump and a working motor; the oil inlet of the working pump is connected to the oil tank, and the oil outlet is connected to the oil inlet P2 of the main valve for diverting and merging; the working motor is connected to the controller. When the control terminal of the first pilot valve loses power, it pushes the main valve of the flow splitting and merging to the right position, and the oil output by the working pump returns through the main valve of the flow splitting and merging to complete the unloading. When the control terminal of the first pilot valve is energized, it pushes the main valve of the flow splitting and merging to the left position. The working pump enters the oil inlet P2 of the main valve of the flow splitting and merging and connects to the high-pressure oil circuit. It merges with the oil inlet P1 of the main valve of the flow splitting and merging and outputs a high flow supply to the boom control unit and / or the bucket control unit.

[0012] This solution is equipped with a large-displacement working pump and a working motor. The working pump provides continuous, high-volume-efficiency, high-flow hydraulic power to meet the needs of heavy-duty operations. The working motor is connected to the controller, and the flow rate is supplied on demand through motor speed regulation, effectively avoiding the overflow loss of traditional constant-speed pumps.

[0013] As an optional implementation, the boom control unit includes a boom coupling, a second pilot valve, and a third pilot valve. The oil inlet of the boom coupling is connected to the oil outlet of the flow divider valve, and the oil outlet is connected to the boom cylinder. The pilot ends on both sides are respectively connected to the second pilot valve and the third pilot valve. The second pilot valve and the third pilot valve are connected to the controller. In response to the opening signal of the working handle, the controller drives the second pilot valve / the third pilot valve to be energized, pushing the boom coupling to the right / left position, connecting the boom cylinder, and performing boom lifting / lowering.

[0014] This solution sets up two pilot valves (the second pilot valve and the third pilot valve) connected to the controller to coordinate the displacement of the main valve core of the boom linkage. This enables fine segmented adjustment of the boom lifting speed (determined by the magnitude of the control current obtained from the second pilot valve / third pilot valve) and direction, thereby improving the precision of composite control.

[0015] As an optional implementation, the bucket rotation control unit includes a bucket rotation coupling, a fourth pilot valve, and a fifth pilot valve; the oil inlet of the bucket rotation coupling is connected to the oil outlet of the diversion and merging valve, the oil outlet is connected to the bucket rotation cylinder, and the pilot ends on both sides are respectively connected to the fourth pilot valve and the fifth pilot valve; the fourth pilot valve and the fifth pilot valve are connected to the controller. In response to the opening signal of the working handle, the controller drives the fourth pilot valve / the fifth pilot valve to be energized, pushes the bucket rotating link to the right / left position, connects the bucket rotating cylinder, and performs bucket rotation to collect / unload.

[0016] This solution is equipped with a fourth pilot valve and a fifth pilot valve connected to the controller. The opening direction and degree of the bucket transfer valve core are independently controlled by the two pilot valves, so as to achieve precise adjustment of the bucket collection and unloading actions.

[0017] As an optional implementation, a pressure sensor is also included, which is connected to the LS port of the steering gear and the controller; The pressure sensor obtains the LS load signal from the LS port of the steering gear and feeds it back to the controller, thereby driving the steering motor to rotate and controlling the steering speed.

[0018] This solution sets up a pressure sensor that connects both the LS port of the steering gear and the controller. It collects the LS load signal (load-sensitive signal) in real time and feeds it back to the controller, enabling the system to dynamically match the pump's output flow and pressure according to the steering load, thereby improving steering response speed and reducing steady-state overflow loss.

[0019] As an optional implementation, it also includes a pilot accumulator, which is connected to the oil inlet of the first pilot valve, the oil inlet of the second pilot valve, the oil inlet of the third pilot valve, the oil inlet of the fourth pilot valve, and the oil inlet of the fifth pilot valve.

[0020] This solution is equipped with a pilot accumulator. When the main engine shuts down or the oil pump loses pressure, the pressure oil stored in the pilot accumulator maintains short-term pilot control capability. During normal operation, it absorbs hydraulic shocks and ensures that the pilot pressure is stable and does not interfere with each other when the boom and bucket are operating simultaneously.

[0021] As an optional implementation, the displacement of the steering pump is smaller than that of the working pump.

[0022] The present invention also provides an electric loader, including a hydraulic control system as described above. Attached Figure Description

[0023] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0024] Figure 1 This is a partial hydraulic schematic diagram of a hydraulic control system provided in an embodiment of the present invention; Figure 2 This is a partial hydraulic schematic diagram of a hydraulic control system provided in an embodiment of the present invention; Icons: 1. Oil tank; 2. Working motor; 3. Working pump; 4. Steering motor; 5. Steering pump; 6. Priority valve; 7. Steering gear; 8. Steering cylinder; 9. Pressure sensor; 10. Diverting and merging valve; 10-1. Diverting and merging main valve; 10-2. First pilot valve; 11. Distribution valve; 11-1. Boom coupling; 11-2. Second pilot valve; 11-3. Third pilot valve; 11-4. Bucket coupling; 11-5. Fourth pilot valve; 11-6. Fifth pilot valve; 12. Boom cylinder; 13. Bucket cylinder; 14. Pilot accumulator. Detailed Implementation

[0025] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. 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.

[0026] In this invention, the terms "upper," "lower," "left," "right," "front," "rear," "top," "bottom," "inner," "outer," "middle," "vertical," "horizontal," "lateral," and "longitudinal" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. These terms are primarily for the purpose of better describing the invention and its embodiments, and are not intended to limit the indicated devices, elements, or components to having a specific orientation, or to be constructed and operated in a specific orientation.

[0027] Furthermore, in addition to indicating direction or positional relationship, some of the aforementioned terms may also have other meanings. For example, the term "above" may also be used in certain situations to indicate a dependency or connection. Those skilled in the art can understand the specific meaning of these terms in this invention based on the specific circumstances.

[0028] Furthermore, the terms "installation," "setup," "equipped with," "connection," and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral structure; 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, or an internal connection between two devices, components, or parts. Those skilled in the art can understand the specific meaning of these terms in this invention based on the specific circumstances.

[0029] Furthermore, the terms "first," "second," etc., are primarily used to distinguish different devices, components, or parts (which may be the same or different in specific type and construction), and are not intended to indicate or imply the relative importance or quantity of the indicated devices, components, or parts. Unless otherwise stated, "a plurality of" means two or more.

[0030] The technical solution of the present invention will be further described below with reference to the embodiments and accompanying drawings.

[0031] Example 1 Please see Figure 1 and Figure 2 As shown, this application embodiment provides a hydraulic control system, including a controller and a distribution valve 11, a flow splitting and merging valve 10, a priority valve 6, a first pump drive unit, and a second pump drive unit connected thereto, and also includes a steering gear 7. The distribution valve 11 includes a boom control unit and a bucket control unit. The oil outlet L and oil outlet R of the steering gear 7 are connected to the steering cylinder 8. The displacement of the first pump-driven unit is smaller than that of the second pump-driven unit. The oil outlet of the first pump drive unit is connected to the priority valve 6, and the oil outlet of the priority valve 6 is connected to the oil inlet of the steering gear 7 and one side oil inlet of the merging and splitting valve 10; the other side oil inlet of the merging and splitting valve 10 is connected to the second pump drive unit, and the oil outlet is connected to the boom control unit and the bucket control unit. Under low flow conditions, the merging and splitting valve 10 is de-energized and in the right position. The second pump drive unit is unloaded under low pressure and connected to the first pump drive unit through the priority valve 6, supplying a low flow to the boom control unit and / or the bucket control unit. Under high flow conditions, the merging and splitting valve 10 is energized and in the left position. The first pump drive unit and the second pump drive unit are simultaneously connected to the high-pressure oil circuit and merged, supplying a high flow to the boom control unit and / or the bucket control unit.

[0032] In this embodiment, the flow splitting and merging valve 10 includes a first pilot valve 10-2 and a flow splitting and merging main valve 10-1; the control terminal of the first pilot valve 10-2 is connected to the controller, and the oil outlet is connected to the control terminal of the flow splitting and merging main valve 10-1; the oil inlet P1 of the flow splitting and merging main valve 10-1 is connected to the first pump drive unit, the oil inlet P2 is connected to the second pump drive unit, and the oil outlet is connected to the boom control unit and the bucket control unit; In response to the opening signal of the working handle, the controller drives the boom control unit and / or the bucket control unit to be turned on, so that the control terminal of the first pilot valve 10-2 is de-energized, pushing the main valve 10-1 to the right position, and then the first pump drive unit is connected through the priority valve 6 to output a low flow supply to the boom control unit and / or the bucket control unit. Alternatively, the control terminal of the first pilot valve 10-2 can be energized and turned on, pushing the main valve 10-1 to the left position, connecting the first pump drive unit and the second pump drive unit to the high-pressure oil circuit simultaneously and achieving merging, thus outputting a high flow supply to the boom control unit and / or the bucket control unit.

[0033] Among them, the main valve 10-1 for diverting and merging flow includes a two-position three-way directional valve; the first pilot valve 10-2 includes a two-position two-way solenoid valve.

[0034] This embodiment employs a first pilot valve 10-2 and a flow-diverting / merging main valve 10-1. The connection between the first pilot valve 10-2 and the controller enables logical coordination between precise pilot control for low flow rates and flow-diverting at high flow rates, achieving energy efficiency management. The external flow-diverting / merging main valve 10-1 can determine whether to merge based on load requirements, avoiding complex merging channels within the main valve body, thus reducing pressure loss and heat generation, and facilitating future maintenance or replacement. Under low flow conditions, the flow-diverting / merging main valve 10-1 operates in the right position, and the second pump drive unit is unloaded at low pressure, achieving high efficiency and energy saving under low flow conditions. Under high flow conditions, the flow-diverting / merging main valve 10-1 operates in the left position, achieving high-pressure merging of the two pumps to meet peak power requirements, reducing standby power consumption while ensuring rapid response and precise control during heavy-duty operations. Furthermore, the flow rate of a single or dual pump can be dynamically allocated to the boom or bucket according to operational needs, achieving coordinated merging of lifting and unloading actions, thereby improving the efficiency of combined actions and avoiding pressure competition.

[0035] In this embodiment, the first pump drive unit includes a steering pump 5 and a steering motor 4 that are electrically connected; the oil inlet of the steering pump 5 is connected to the oil tank 1, and the oil outlet is connected to the priority valve 6; the steering motor 4 is connected to the controller. When the steering gear 7 is triggered, it pushes the priority valve 6 to the left position. Then, the oil inlet and oil outlet CF of the priority valve 6 are connected, and oil is supplied to the steering gear 7 to perform steering. Otherwise, if the priority valve 6 is in the right position, the oil inlet and outlet EF of the priority valve 6 are connected, connecting the steering pump 5 and the flow divider / merge valve 10 to perform a small-flow loading and unloading operation.

[0036] This embodiment is equipped with a small-displacement steering pump 5 and a steering motor 4 corresponding to the steering gear 7, which can realize independent control of the speed of the steering pump 5 as needed; through the connection between the steering motor 4 and the controller, the flow requirements of the micro-control section are met, thereby enabling precise adjustment of flow and pressure according to the actual load, significantly reducing energy loss under non-steering conditions, and avoiding energy loss caused by throttling of the distribution valve 11.

[0037] In this embodiment, a pressure sensor 9 is also included, which is connected to the LS port of the steering gear 7 and the controller; The pressure sensor 9 obtains the LS load signal from the LS port of the steering gear 7 and feeds it back to the controller, thereby driving the steering motor 4 to rotate and controlling the steering speed.

[0038] In this embodiment, a pressure sensor 9 is set to simultaneously connect the LS port of the steering gear 7 and the controller to collect the LS load signal (load sensitive signal) in real time and feed it back to the controller. This allows the system to dynamically match the output flow and pressure of the pump according to the steering load, thereby improving the steering response speed and reducing steady-state overflow loss.

[0039] The steering principle of this embodiment is as follows: When the steering gear 7 is triggered and the valve core is in the left position, the LS port and the oil inlet P of the steering gear 7 are connected. The high-pressure oil reaches the left end of the priority valve 6 through the LS port, pushing the valve core of the priority valve 6 to the left position. At this time, the CF port reaches its maximum. The high-pressure oil passing through the oil inlet P of the steering gear 7 reaches the oil outlet L of the steering gear 7 through the left position, and then achieves left turn through the steering cylinder 8. The oil at the other end of the steering cylinder 8 returns to the oil tank 1 through the oil outlet R of the steering gear 7, and the whole machine completes the left turn.

[0040] The same applies when steering gear 7 is in the right position; the entire machine completes a right turn.

[0041] The LS port is equipped with a pressure sensor 9, which detects the steering pressure of the LS port to determine the steering speed. The controller controls the speed of the steering motor 4 through the pressure signal (LS load signal) of the LS port, thereby realizing the steering speed.

[0042] This embodiment uses a separate steering motor 4 to drive a small-displacement steering pump 5, achieving on-demand steering power while avoiding losses caused by large flow rates passing through the priority valve 6. If the maximum steering flow rate is met, according to the formula, the pump displacement can be reduced several times, using the rotational speed to compensate for the maximum flow rate requirement during steering. Simultaneously, the rotational speed of the steering pump 5 can be controlled to meet the low-flow steering requirements, avoiding the throttling losses of the existing loader's steering gear 7 and improving steering stability. The flow rate calculation formula is as follows:

[0043] In the formula, Q represents the flow rate supplied by steering pump 5; q represents the displacement of steering pump 5; n represents the motor speed; and η represents the pump efficiency.

[0044] In this embodiment, the second pump drive unit includes a working pump 3 and a working motor 2; the oil inlet of the working pump 3 is connected to the oil tank 1, and the oil outlet is connected to the oil inlet P2 of the main valve 10-1; the working motor 2 is connected to the controller. When the control terminal of the first pilot valve 10-2 is de-energized, it pushes the main valve 10-1 to the right position, and the oil output by the working pump 3 returns through the main valve 10-1 to complete the unloading. When the control terminal of the first pilot valve 10-2 is energized, it pushes the main valve 10-1 to the left position. The working pump 3 enters the oil inlet P2 of the main valve 10-1 and connects to the high-pressure oil circuit. It merges with the oil inlet P1 of the main valve 10-1 and outputs a high flow supply to the boom control unit and / or the bucket control unit.

[0045] In this embodiment, the displacement of the steering pump 5 is less than that of the working pump 3.

[0046] This embodiment is equipped with a large-displacement working pump 3 and a working motor 2. The working pump 3 provides continuous, high-volume-efficiency, high-flow hydraulic power to meet the needs of heavy-duty operations. The working motor 2 is connected to the controller, and the flow rate is supplied on demand through motor speed regulation, effectively avoiding the overflow loss of traditional constant-speed pumps.

[0047] In this embodiment, the boom control unit includes a boom coupling 11-1, a second pilot valve 11-2, and a third pilot valve 11-3. The oil inlet of the boom coupling 11-1 is connected to the oil outlet of the flow divider / combiner valve 10, and the oil outlet is connected to the boom cylinder 12. The two pilot ends are respectively connected to the second pilot valve 11-2 and the third pilot valve 11-3. The second pilot valve 11-2 and the third pilot valve 11-3 are connected to the controller. In response to the opening signal of the working handle, the controller drives the second pilot valve 11-2 / the third pilot valve 11-3 to be energized, pushing the boom coupling 11-1 to the right / left position, connecting the boom cylinder 12, and performing boom lifting / lowering.

[0048] This embodiment sets up two pilot valves (second pilot valve 11-2 and third pilot valve 11-3) connected to the controller to coordinate the displacement of the main valve core of the boom linkage 11-1. This enables fine segmented adjustment of the boom lifting speed (determined by the magnitude of the control current obtained from the second pilot valve 11-2 / third pilot valve 11-3) and direction, thereby improving the precision of composite control.

[0049] In this embodiment, the bucket rotation control unit includes a bucket rotation coupling 11-4, a fourth pilot valve 11-5, and a fifth pilot valve 11-6; the oil inlet of the bucket rotation coupling 11-4 is connected to the oil outlet of the diversion and merging valve 10, and the oil outlet is connected to the bucket rotation cylinder 13; the pilot ends on both sides are respectively connected to the fourth pilot valve 11-5 and the fifth pilot valve 11-6; the fourth pilot valve 11-5 and the fifth pilot valve 11-6 are connected to the controller. In response to the opening signal of the working handle, the controller drives the fourth pilot valve 11-5 / the fifth pilot valve 11-6 to be energized, pushing the bucket rotating link 11-4 to the right / left position, connecting the bucket rotating cylinder 13, and performing bucket rotation to collect / unload.

[0050] Specifically, loaders require relatively small flow rates when digging, unloading, lowering the boom, or performing micro-control.

[0051] When the operating handle causes the bucket to unload (the fourth pilot valve 11-5 is energized), the bucket coupling 11-4 is pushed to the left position. At this time, the first pilot valve 10-2 is de-energized, causing the main valve 10-1 to be in the right position. Simultaneously, the oil from the large-displacement working pump 3 returns to the oil tank 1 through the main valve 10-1 to complete low-pressure unloading. The high-pressure oil from the steering pump 5 passes through the main valve 10-1, enters the bucket coupling 11-4 through the inlet P0 port of the distribution valve 11, and then enters the small chamber of the bucket cylinder 13 through the left position of the bucket coupling 11-4. The hydraulic oil from the large chamber of the bucket cylinder 13 enters the oil tank 1 through the left position of the bucket coupling 11-4, completing the unloading action. The speed of the steering pump 5 can be controlled by detecting the handle angle.

[0052] When the bucket is rotated and retracted, the fifth pilot valve 11-6 is energized, and its working principle is the same as above.

[0053] In this embodiment, a fourth pilot valve 11-5 and a fifth pilot valve 11-6 connected to the controller are provided. The opening direction and degree of the bucket-turning valve core 11-4 are controlled independently by the two pilot valves to achieve precise adjustment of the bucket-collecting and unloading actions.

[0054] In this embodiment, a pilot accumulator 14 is also included, which is connected to the oil inlet of the first pilot valve 10-2, the oil inlet of the second pilot valve 11-2, the oil inlet of the third pilot valve 11-3, the oil inlet of the fourth pilot valve 11-5, and the oil inlet of the fifth pilot valve 11-6.

[0055] Among them, the second pilot valve 11-2, the third pilot valve 11-3, the fourth pilot valve 11-5, and the fifth pilot valve 11-6 are all proportional solenoid valves.

[0056] In this embodiment, a pilot accumulator 14 is provided. When the main engine is shut down or the oil pump loses pressure, the pressure oil stored in the pilot accumulator 14 is used to maintain short-term pilot control capability. During normal operation, it absorbs hydraulic shock and ensures that the pilot pressure is stable and does not interfere with each other when the boom linkage 11-1 and the bucket linkage 11-4 operate simultaneously.

[0057] See Figure 1 This embodiment also includes a hydraulic control circuit CIR consisting of a pilot pressure reducing valve and a pilot relief valve, relief valves AIR and BIR acting on the bucket cylinder, and a main relief valve MR acting on the distribution valve.

[0058] In this embodiment, the specific loading and unloading operation principle is as follows: After the high-pressure oil from the steering pump 5 passes through the priority valve 6, if the pressure sensor 9 has no signal, the oil from the steering pump 5 can pass through the EF port of the priority valve 6, and then through the merging and splitting valve 10 to reach the oil inlet P of the distribution valve 11, thus meeting the high-pressure oil requirements of the boom cylinder 12 and the bucket cylinder 13.

[0059] 1. When the working handle is not operated, the controller does not move, the first pilot valve 10-2 is de-energized, the main valve 10-1 is in the right position, and the oil of the steering pump 5 returns to the oil tank 1 through the middle position of the distribution valve 11 (boom connection 11-1, bucket connection 11-4) to complete the low-pressure unloading; at the same time, the oil of the working pump 3 returns to the oil tank 1 through the main valve 10-1 to complete the low-pressure unloading.

[0060] 2. When the working handle is opened at a small angle (i.e., the control current is small) When the boom is raised by a small angle using the control handle (a small current is supplied to the third pilot valve 11-3), the boom coupling 11-1 is opened slightly. At this time, the first pilot valve 10-2 is de-energized via the controller, and the main valve 10-1 is in the right position. The hydraulic fluid from the working pump 3 returns separately through the main valve 10-1 to complete the unloading. The high-pressure oil from the steering pump 5 passes through the main valve 10-1 and the valve core of the boom coupling 11-1 to the outlet A2, and then enters the large chamber of the boom cylinder 12. The hydraulic oil from the small chamber of the boom cylinder 12 returns to the oil tank 1 after passing through the outlet B2 and the valve core of the boom coupling 11-1, causing the boom cylinder 12 to rise slowly. At this time, the speed of the steering motor 4 can be controlled by detecting the angle of the control handle.

[0061] When the a1 handle is pushed open at a small angle, the second pilot solenoid valve opens at a small angle, and the micro-control action of lowering the boom is performed as above.

[0062] The loader requires a small flow rate when digging, unloading, lowering the boom, or performing micro-control, so only the flow rate of steering pump 5 needs to be applied.

[0063] 3. When the working handle is opened at a large angle (i.e., when the control current is large) When the boom is raised to a large angle by the operating handle (responding to a large current to the third pilot valve 11-3), the boom coupling 11-1 is fully opened. At this time, the first pilot valve 10-2 is energized via the controller, and the main flow control valve 10-1 is in the left position. The hydraulic oil from the working pump 3 merges with the high-pressure oil from the steering pump 5 through the main flow control valve 10-1, and is output to the outlet A2 through the valve core of the boom coupling 11-1. Then, it enters the large chamber of the boom cylinder 12. The hydraulic oil in the small chamber of the boom cylinder 12 returns to the oil tank 1 after passing through the outlet B2 and the valve core of the boom coupling 11-1, causing the boom cylinder 12 to rise rapidly. At this time, the speed of the working motor 2 can be controlled by detecting the angle of the operating handle.

[0064] When the boom and bucket move simultaneously, if the required flow rate is small, the first pilot valve 10-2 is de-energized, and only the steering pump 5 is connected to the oil circuit; when the required flow rate is large, the first pilot valve 10-2 is energized, and the two pumps are combined.

[0065] Example 2 This invention also provides an electric loader, including a hydraulic control system as described in Embodiment 1 above.

[0066] This embodiment of the invention sets up two power sources: a first pump drive unit and a second pump drive unit. Under low-flow conditions, the merging and splitting valve 10 is de-energized and in the right position, enabling low-pressure unloading of the second pump drive unit, significantly reducing no-load energy consumption. Simultaneously, the priority valve 6 ensures that the first pump drive unit provides precise low-flow supply to the boom and bucket control units, improving energy utilization. Under high-flow conditions, the merging and splitting valve 10 is energized and in the left position, executing high-pressure merging of the two pumps and outputting a large flow rate to meet the demands of heavy-duty operations such as boom lifting and bucket digging (meeting working time requirements). Thus, by switching valve positions, a flexible mode of "one pump saving energy, two pumps adapting to large flow" is achieved, avoiding energy loss caused by throttling of the distribution valve 11, ensuring response speed and work efficiency under heavy loads, further reducing the loader's energy consumption and improving operational flexibility.

[0067] The technical means disclosed in this invention are not limited to those disclosed in the above embodiments, but also include technical solutions composed of any combination of the above technical features. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principles of this invention, and these improvements and modifications are also considered within the scope of protection of this invention.

Claims

1. A hydraulic control system, characterized by: It includes a controller and connected to it a distribution valve, a merging / diverging valve, a priority valve, a first pump drive unit, and a second pump drive unit, and also includes a steering gear. The distribution valve includes a boom control unit and a bucket control unit. The oil outlet of the first pump drive unit is connected to the priority valve, and the oil outlet of the priority valve is connected to the oil inlet of the steering gear and one side of the oil inlet of the merging and splitting valve; the other side of the oil inlet of the merging and splitting valve is connected to the second pump drive unit, and the oil outlet is connected to the boom control unit and the bucket control unit. Under low flow conditions, the merging and splitting valve is de-energized and in the right position. The second pump drive unit is unloaded at low pressure and connected to the first pump drive unit through the priority valve, supplying a low flow to the boom control unit and / or the bucket control unit. Under high flow conditions, the merging and splitting valve is energized and in the left position. The first pump drive unit and the second pump drive unit are simultaneously connected to the high-pressure oil circuit and merged, supplying a high flow to the boom control unit and / or the bucket control unit.

2. A hydraulic control system as claimed in claim 1, characterised in that: The flow splitting and merging valve includes a first pilot valve and a flow splitting and merging main valve; the control terminal of the first pilot valve is connected to the controller, and the oil outlet is connected to the control terminal of the flow splitting and merging main valve; the oil inlet P1 of the flow splitting and merging main valve is connected to the first pump drive unit, the oil inlet P2 is connected to the second pump drive unit, and the oil outlet is connected to the boom control unit and the bucket control unit. In response to the opening signal of the working handle, the controller drives the boom control unit and / or the bucket control unit to be turned on, so that the control end of the first pilot valve is de-energized, pushing the main valve of the flow divider and merge to the right position, and then the first pump drive unit is connected through the priority valve to output a low flow supply to the boom control unit and / or the bucket control unit. Alternatively, the control terminal of the first pilot valve can be energized and turned on, pushing the main valve of the flow splitting and merging to the left position, connecting the first pump drive unit and the second pump drive unit to the high-pressure oil circuit at the same time and achieving flow merging, so as to output a high flow supply to the boom control unit and / or the bucket control unit.

3. A hydraulic control system as claimed in claim 2, characterised in that: The first pump drive unit includes a steering pump and a steering motor that are electrically connected; the oil inlet of the steering pump is connected to the oil tank, and the oil outlet is connected to the priority valve; the steering motor is connected to the controller. When the steering gear is triggered, it pushes the priority valve to the left position. Then, the oil inlet and outlet CF of the priority valve are connected, supplying oil to the steering gear and performing steering. Otherwise, if the priority valve is in the right position, the oil inlet and outlet EF of the priority valve are connected, connecting the steering pump and the flow divider / merge valve to perform small-flow loading and unloading operations.

4. A hydraulic control system as claimed in claim 3, characterised in that: The second pump drive unit includes a working pump and a working motor; the oil inlet of the working pump is connected to the oil tank, and the oil outlet is connected to the oil inlet P2 of the main valve for diverting and merging; the working motor is connected to the controller. When the control terminal of the first pilot valve loses power, it pushes the main valve of the flow splitting and merging to the right position, and the oil output by the working pump returns through the main valve of the flow splitting and merging to complete the unloading. When the control terminal of the first pilot valve is energized, it pushes the main valve of the flow splitting and merging to the left position. The working pump enters the oil inlet P2 of the main valve of the flow splitting and merging and connects to the high-pressure oil circuit. It merges with the oil inlet P1 of the main valve of the flow splitting and merging and outputs a high flow supply to the boom control unit and / or the bucket control unit.

5. A hydraulic control system as described in claim 1, characterized in that: The boom control unit includes a boom coupling, a second pilot valve, and a third pilot valve. The oil inlet of the boom coupling is connected to the oil outlet of the flow divider valve, and the oil outlet is connected to the boom cylinder. The pilot ends on both sides are connected to the second pilot valve and the third pilot valve, respectively. The second pilot valve and the third pilot valve are connected to the controller. In response to the opening signal of the working handle, the controller drives the second pilot valve / the third pilot valve to be energized, pushing the boom coupling to the right / left position, connecting the boom cylinder, and performing boom lifting / lowering.

6. A hydraulic control system as described in claim 5, characterized in that: The bucket rotation control unit includes a bucket rotation coupling, a fourth pilot valve, and a fifth pilot valve; the oil inlet of the bucket rotation coupling is connected to the oil outlet of the diversion and merging valve, the oil outlet is connected to the bucket rotation cylinder, and the pilot ends on both sides are respectively connected to the fourth pilot valve and the fifth pilot valve; the fourth pilot valve and the fifth pilot valve are connected to the controller. In response to the opening signal of the working handle, the controller drives the fourth pilot valve / the fifth pilot valve to be energized, pushes the bucket rotating link to the right / left position, connects the bucket rotating cylinder, and performs bucket rotation to collect / unload.

7. A hydraulic control system as described in claim 1, characterized in that: It also includes a pressure sensor, which is connected to the LS port of the steering gear and the controller; The pressure sensor obtains the LS load signal from the LS port of the steering gear and feeds it back to the controller, thereby driving the steering motor to rotate and controlling the steering speed.

8. A hydraulic control system as described in claim 6, characterized in that: It also includes a pilot accumulator, which is connected to the oil inlet of the first pilot valve, the oil inlet of the second pilot valve, the oil inlet of the third pilot valve, the oil inlet of the fourth pilot valve and the oil inlet of the fifth pilot valve.

9. A hydraulic control system as described in claim 4, characterized in that: The displacement of the steering pump is less than that of the working pump.

10. An electric loader, characterized in that: Includes a hydraulic control system as described in any one of claims 1 to 9.

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