Low-power-consumption hydraulic system of electric loader

Abstract

The invention relates to the technical field of loader hydraulic control, in particular to a low-power-consumption hydraulic system of an electric loader, aiming at steering and normal work of the loader, a first power module and a second power module which are independently regulated and controlled are respectively arranged, and independent valve port control is adapted by utilizing the coordination effect of a flow scheduling module and a pressure matching module; a throttling link is completely eliminated, an inlet valve port and an outlet valve port are fully opened, the pressure loss of oil flowing through the valve ports is reduced to the minimum, and the energy consumption of a whole machine steering loop is greatly reduced; and meanwhile, independent and accurate control over oil inlet and oil return of the oil cylinder is achieved through speed regulation of variable rotating speed and variable displacement, real stepless speed regulation is achieved by avoiding limitation of the opening degree of a main valve port, and therefore the energy efficiency of the system is greatly improved.

Description

Technical Field

[0001] This invention relates to the field of hydraulic control technology for loaders, and more particularly to a low-power hydraulic system for an electric loader. Background Technology

[0002] In recent years, electric loaders have been widely used in the market due to their excellent energy-saving characteristics and low noise, and have been exported in large quantities to the international high-end market. Statistical analysis of the data shows that the energy saving of electric loaders is mainly due to the high efficiency of batteries compared to engines and the significant benefits of eliminating the torque converter, while the contribution of the hydraulic system is relatively small.

[0003] Referring to Chinese patent CN103711172B, "Four-Pump Quantitative Combination Hydraulic System for Loaders," the variable hydraulic system currently used in electric loaders operates on the principle of primarily consisting of a variable steering pump, a variable working pump, a priority valve, a steering gear, a distribution valve, a pilot valve, and a shuttle valve. During hydraulic operation, the flow rate of the steering pump combines with that of the working pump through the priority valve, jointly supplying oil to the working hydraulic system. However, because the steering load and working load typically differ significantly, the throttling loss on the priority valve is substantial, resulting in significant pressure loss during the combined flow of the combined action. Limited by the hydraulic system itself, the entire machine suffers from the following problems: (1) There is throttling loss when the combined action is combined, resulting in high energy consumption of the whole machine; (2) For load-sensitive multi-way valves with valve post-compensation, the pressure loss of the system is large when it is in single operation due to the presence of the compensator, and the overall energy-saving advantage of the system is not obvious. (3) Although both the variable pump and the motor can be speed-adjusted, the speed regulation of the system is still constrained by the opening of the main valve, and the advantages of the variable pump's adjustable displacement and the motor's variable speed regulation are not fully utilized.

[0004] The aforementioned factors have limited the further improvement of the energy efficiency of electric loaders. Summary of the Invention

[0005] This invention provides a low-power hydraulic system for electric loaders, which solves the technical problems of high energy consumption and poor energy efficiency in existing loader hydraulic systems, such as large throttling losses due to priority valve confluence, high single-action pressure loss of load-sensitive multi-way valve compensators, and the limitation of variable pump and motor speed regulation by the opening of the main valve.

[0006] To solve the above technical problems, the present invention provides a low-power hydraulic system for an electric loader, including a main controller and a first power module and a second power module connected to the main controller, as well as a steering module and a working module; The first power module includes a first flow scheduling module and a first pressure matching module. The first flow scheduling module is connected to the main controller and the first pressure matching module. The first pressure matching module is connected to the main controller, the fuel tank, and the steering module. The second power module includes a second flow scheduling module and a second pressure matching module. The second flow scheduling module is connected to the main controller and the second pressure matching module. The second pressure matching module is connected to the main controller, the oil tank, and the working module. The steering module and the working module are controlled by independent valve ports. When the actuator is triggered, the main controller drives the first pressure matching module and / or the second pressure matching module to adjust the displacement to maintain a constant pressure difference, ensuring pressure matching and power response. Then, according to the total flow demand, the main controller controls the first flow scheduling module and / or the second flow scheduling module to smoothly adjust the speed to the target speed, perform flow matching, and perform volumetric speed regulation.

[0007] This basic solution addresses the steering and normal operation of the loader by setting up independently controlled first and second power modules. Utilizing the coordinated action of the flow scheduling module and pressure matching module, it adapts to independent valve control, completely eliminating throttling and fully opening the inlet and outlet valves. This minimizes pressure loss of the oil flowing through the valves, significantly reducing the energy consumption of the entire steering circuit. Simultaneously, through variable speed and displacement speed regulation, it achieves independent and precise control of the oil inlet and outlet of the cylinders, and avoids the constraints of the main valve opening to achieve true stepless speed regulation, thereby greatly improving system energy efficiency.

[0008] In a further embodiment, the first flow scheduling module includes a steering controller and a steering motor. The steering controller is connected to the main controller and the steering motor, and is used to smoothly adjust the speed of the steering motor to the target speed according to the drive of the main controller when the actuator is triggered to adapt to the total flow demand. The second flow scheduling module includes a working controller and a working motor. The working controller is connected to the main controller and the working motor, and is used to smoothly adjust the speed of the working motor to the target speed according to the drive of the main controller when the actuator is triggered to adapt to the total flow demand.

[0009] This solution sets up two independent flow scheduling modules (first flow scheduling module and second flow scheduling module) connected to the main controller, which provide power sources specifically for the loader's steering and working functions (boom lifting and bucket control). The power source is replaced with an electronic control method, and the throttling link in the circuit is eliminated. The volume is adjusted to a second level by changing the motor speed (the displacement is adjusted to a first level), thereby significantly reducing the overall energy consumption of the machine.

[0010] In a further embodiment, the first pressure matching module includes a steering variable pump, a replenishing pump, a first check valve, a replenishing overflow valve, a high-pressure overflow valve, and a flushing valve; the variable pump is mechanically connected to the steering motor and electrically connected to the main controller, its inlet is connected to the replenishing pump and the oil tank, and its outlet is connected to the inlet of the steering module. The inlet of the first check valve is connected to the outlet of the replenishing pump and the replenishing overflow valve, and the outlet is connected to the inlet Pa and inlet Pb of the steering module. The high-pressure overflow valve is connected to the oil inlet and oil tank of the steering module; the flushing valve is connected to the oil inlet and oil tank of the steering module.

[0011] This solution uses a closed-loop bidirectional variable pump consisting of a steering variable pump, a replenishing pump, a first check valve, a replenishing overflow valve, a high-pressure overflow valve, and a flushing valve. The output flow rate is only related to the pump's displacement and speed, and is basically independent of the load pressure. It transforms valve-controlled throttling into pump-controlled solvent control, and then adjusts it steplessly and proportionally, so that the steering speed and the steering wheel's angular velocity and angle form a precise and linear correspondence, greatly improving the driving experience. The closed-loop bidirectional variable pump system has short pipelines and directly responds to electrical signals, thereby improving the sensitivity of steering action response.

[0012] In a further embodiment, the second pressure matching module includes a variable pump, a pressure shut-off valve, and an electro-proportional valve, wherein the electro-proportional valve is connected to the variable pump, the pressure shut-off valve, and the main controller. The electro-proportional valve is used to adjust the displacement of the working variable pump according to the drive signal output by the main controller to maintain a constant pressure difference and ensure pressure matching and power response. The variable displacement pump is used to control the electro-proportional valve to reduce the pump's displacement to the minimum displacement when the system pressure exceeds the set pressure value.

[0013] This solution uses an electro-proportional valve to control the displacement of the variable pump, improving upon existing throttling regulation to flow matching. This allows the output flow of the variable pump to precisely match the required flow of the boom cylinder. The structure is simple and compact, eliminating throttling and overflow losses. This not only achieves good energy-saving effects but also improves the smoothness and precision of operation. Furthermore, by eliminating the two main heat sources—throttling and high-pressure overflow—the oil temperature in the hydraulic system is reduced, thereby improving system reliability.

[0014] In a further embodiment, the working module includes a boom control valve, a bucket control valve, a working relief valve, a boom cylinder, and a bucket cylinder. The oil outlet of the second pressure matching module is connected to the oil inlet of the boom control valve, the oil inlet of the bucket control valve, and the working relief valve. The oil outlet of the boom control valve is connected to the boom cylinder, and the oil outlet of the bucket control valve is connected to the bucket cylinder.

[0015] In a further embodiment, the boom control valve includes a first boom solenoid valve, a second boom solenoid valve, a replenishing check valve, and a second check valve; the oil inlet of the second check valve is connected to the oil outlet of the second pressure matching module, and the oil outlet is connected to the oil inlets of the first boom solenoid valve and the second boom solenoid valve. The oil outlet of the first boom solenoid valve is connected to the oil inlet Pa of the boom cylinder; the oil outlet of the second boom solenoid valve is connected to the oil inlet Pb of the boom cylinder. The oil inlet of the replenishing check valve is connected to the oil return port of the first boom solenoid valve and the second boom solenoid valve, and the oil outlet is connected to the oil inlet Pb of the boom cylinder. The first boom solenoid valve and the second boom solenoid valve are electrically connected to the main controller.

[0016] This solution addresses the motion control of the boom cylinder by setting up independent boom solenoid valves (configured one-to-one with the cylinders). Utilizing proportional solenoid valves, electrical signals are received and the valve core opening is infinitely adjusted, thereby precisely controlling the flow rate into the cylinder and achieving refined and accurate hydraulic operation control. A replenishing check valve prevents cavitation and air intake, ensuring smooth operation. A second check valve acts as an anti-nodding check valve, firmly locking the oil in the rodless chamber to prevent the boom from accidentally falling due to gravity, ensuring the safety of equipment and personnel.

[0017] In a further embodiment, the bucket control valve includes a first bucket solenoid valve, a second bucket solenoid valve, a third check valve, a first overload replenishing valve, and a second overload replenishing valve. The oil inlet of the third check valve is connected to the oil outlet of the second pressure matching module, and the oil outlet is connected to the oil inlet of the first bucket solenoid valve and the second bucket solenoid valve. The inlet of the first overload replenishing valve is connected to the outlet of the first bucket solenoid valve, and the outlet is connected to the return port; the inlet of the second overload replenishing valve is connected to the outlet of the second bucket solenoid valve, and the outlet is connected to the return port. The oil outlet of the first bucket solenoid valve is connected to the oil inlet Pa of the bucket cylinder, and the oil outlet of the second bucket solenoid valve is connected to the oil inlet Pb of the bucket cylinder. The first bucket solenoid valve and the second bucket solenoid valve are electrically connected to the main controller.

[0018] This design sets up a first and second bucket solenoid valve as independent valve ports for control. By receiving electrical signals, it precisely controls the direction, flow rate, and pressure of the hydraulic oil flowing to the bucket cylinder, achieving stepless flow regulation. A third check valve is set up as an anti-head-diving check valve to prevent the bucket from automatically sinking, avoiding danger caused by the bucket falling unexpectedly when the equipment is stopped for maintenance or waiting, effectively improving the safety of bucket operation. A pair of first and second overload replenishing valves are set up to provide overpressure protection and vacuum replenishing protection for both working chambers of the cylinder.

[0019] In a further embodiment, a radiator is also included, which is connected to the oil return port of the boom control valve, the oil return port of the bucket control valve, and also to the oil tank.

[0020] This solution is based on setting up radiators connected to the return ports of the boom control valve and the bucket control valve to cool the oil, thereby effectively preventing the oil from deteriorating at high temperatures and ensuring the reliable and efficient operation of the system.

[0021] In a further embodiment, the actuator includes a steering wheel and a control handle connected to the main controller.

[0022] In a further embodiment, the steering module includes a left steering cylinder and a right steering cylinder. Attached Figure Description

[0023] Figure 1 This is a system framework diagram of a low-power hydraulic system for an electric loader provided in an embodiment of the present invention; Figure 2 This is a structural diagram of a low-power hydraulic system for an electric loader provided in an embodiment of the present invention; Figure 3 This is provided by the embodiments of the present invention. Figure 2 Structural diagram of the first pressure matching module; Figure 4 This is provided by the embodiments of the present invention. Figure 2 Structural diagram of the second pressure matching module; Figure 5 This is provided by the embodiments of the present invention. Figure 2 Structural diagram of the boom control valve; Figure 6 This is provided by the embodiments of the present invention. Figure 2 Structural diagram of the control valve for the middle bucket; The system includes: a main controller 1, a steering wheel 2, and an operating handle 3; a first flow scheduling module 4, a steering controller 41, and a steering motor 42; a first pressure matching module 5, a steering variable pump 51, a replenishing pump 52, a first check valve 53, a replenishing overflow valve 54, a high-pressure overflow valve 55, and a flushing valve 56; a steering module 6; a second flow scheduling module 7, a work controller 71, and a work motor 72; a second pressure matching module 8, a work variable pump 81, a pressure shut-off valve 82, and an electro-proportional valve 83; a work module 9, a boom control valve 91, a bucket control valve 92, a work overflow valve 93, a boom cylinder 94, a bucket cylinder 95, and a radiator 96; and an oil tank 0. First boom solenoid valve E1, second boom solenoid valve E2, oil replenishment check valve E3, second check valve E4; First bucket solenoid valve F1, second bucket solenoid valve F2, third check valve F3, first overload replenishing valve F4, second overload replenishing valve F5. Detailed Implementation

[0024] The embodiments of the present invention are described in detail below with reference to the accompanying drawings. The embodiments are given for illustrative purposes only and should not be construed as limiting the present invention. The accompanying drawings are for reference and illustration only and do not constitute a limitation on the scope of patent protection of the present invention, because many changes can be made to the present invention without departing from the spirit and scope of the present invention.

[0025] This invention provides a low-power hydraulic system for an electric loader, such as... Figures 1-6 As shown, in this embodiment, it includes a main controller 1 and a first power module and a second power module connected to the main controller 1, as well as a steering module and a working module; The first power module includes a first flow scheduling module 4 and a first pressure matching module 5. The first flow scheduling module 4 is connected to the main controller 1 and the first pressure matching module 5. The first pressure matching module 5 is connected to the main controller 1, the fuel tank 0, and the steering module 6. The second power module includes a second flow scheduling module 7 and a second pressure matching module 8. The second flow scheduling module 7 is connected to the main controller 1 and the second pressure matching module 8. The second pressure matching module 8 is connected to the main controller 1, the oil tank 0, and the working module 9. The steering module and the working module are controlled by independent valve ports. When the actuator is triggered, the main controller 1 drives the first pressure matching module 5 and / or the second pressure matching module 8 to adjust the displacement to maintain a constant pressure difference, ensuring pressure matching and power response. Then, according to the total flow demand, the main controller 1 controls the first flow scheduling module 4 and / or the second flow scheduling module 7 to smoothly adjust the speed to the target speed, perform flow matching, and perform volumetric speed regulation.

[0026] Among them, the main controller 1 is preferably the whole machine controller.

[0027] In this embodiment, the first flow scheduling module 4 includes a steering controller 41 and a steering motor 42. The steering controller 41 is connected to the main controller 1 and the steering motor 42, and is used to smoothly adjust the speed of the steering motor 42 to the target speed according to the drive of the main controller 1 when the actuator is triggered to adapt to the total flow demand. The second flow scheduling module 7 includes a working controller 71 and a working motor 72. The working controller 71 is connected to the main controller 1 and the working motor 72. When the actuator is triggered, the working motor 72 is smoothly adjusted to the target speed according to the drive of the main controller 1 to adapt to the total flow demand.

[0028] This embodiment sets up two independent flow scheduling modules (first flow scheduling module 4 and second flow scheduling module 7) connected to the main controller 1, which provide power sources for the loader's steering and working functions (boom lifting and bucket control). The power source is replaced with an electronic control method, and the throttling link in the circuit is eliminated. The volume is adjusted to a second-level adjustment (the displacement is adjusted to a first-level adjustment) by changing the motor speed, thereby significantly reducing the overall energy consumption of the machine.

[0029] In this embodiment, see Figure 3 The first pressure matching module 5 includes a steering variable pump 51, a replenishing pump 52, a first check valve 53, a replenishing overflow valve 54, a high-pressure overflow valve 55, and a flushing valve 56; the variable pump is mechanically connected to the steering motor 42 and electrically connected to the main controller 1, its oil inlet is connected to the replenishing pump 52 and the oil tank 0, and its oil outlet is connected to the oil inlet of the steering module 6; The oil inlet of the first one-way valve 53 is connected to the oil outlet of the oil replenishment pump 52 and the oil replenishment overflow valve 54, and the oil outlet is connected to the oil inlet Pa and oil inlet Pb of the steering module 6. The high-pressure overflow valve 55 is connected to the oil inlet and oil tank 0 of the steering module 6; the flushing valve 56 is connected to the oil inlet and oil tank 0 of the steering module 6.

[0030] The replenishing pump 52 is used to replenish the leaked oil in the closed system, and the maximum pressure is limited by the replenishing overflow valve 54. The replenishing overflow valve 54 is used to limit the maximum pressure of the replenishing circuit, protect the replenishing pump 52 from damage, and set the pressure of the low-pressure pipeline to redirect the back pressure of the system. The first check valve 53 is used to input the oil from the replenishing pump 52 to the low-pressure side of the circuit. High-pressure relief valve 55 is installed in pairs at the Pa and Pb working oil ports. When the system pressure surge exceeds the set value, it opens to overflow and protect the main pump (steering variable pump 51) from damage. The flushing valve 56 is used to cut off a portion of the "hot" oil on the low-pressure side and flow it back to the oil tank 0 through the flushing valve 56 in order to cool the system.

[0031] Among them, since the power source of the steering module 6 is a closed bidirectional variable pump, the steering signal is input through the electric steering wheel 2, and the steering variable pump 51 and the steering motor 42 cooperate to adjust the flow rate. There are no high-pressure loss components such as priority valves and steering gears in the system. Except for a very small friction loss, the output pressure of the steering motor 42 can be directly applied to the cylinder with almost no pressure loss, which can improve the efficiency of the steering circuit by more than 20%.

[0032] This embodiment sets up a closed-loop bidirectional variable pump consisting of a steering variable pump 51, a replenishing pump 52, a first one-way valve 53, a replenishing overflow valve 54, a high-pressure overflow valve 55, and a flushing valve 56. The output flow rate is only related to the pump's displacement and speed, and is basically independent of the load pressure. It changes from valve-controlled throttling to pump-controlled solvent, and then adjusts it steplessly and proportionally, so that the steering speed and the angular velocity and angle of the steering wheel 2 form a precise and linear correspondence, which greatly improves the driving experience. The closed-loop bidirectional variable pump system has a short pipeline and directly responds to electrical signals, thereby improving the sensitivity of steering action response.

[0033] In this embodiment, see Figure 4 The second pressure matching module 8 includes a working variable pump 81, a pressure shut-off valve 82, and an electro-proportional valve 83, wherein the electro-proportional valve 83 is connected to the working variable pump 81, the pressure shut-off valve 82, and the main controller 1. The electro-proportional valve 83 is used to adjust the displacement of the working variable pump 81 according to the drive signal output by the main controller 1 to maintain a constant pressure difference and ensure pressure matching and power response. The variable displacement pump 81 is used to control the electro-proportional valve 83 to reduce the pump's displacement to the minimum displacement when the system pressure exceeds the set pressure value.

[0034] Preferably, the variable displacement pump 81 and the electro-proportional valve 83 form an electro-proportional variable displacement pump. Taking the two-position three-way valve pressure shut-off valve 82 as an example: When the system pressure exceeds the set pressure value, the pressure shut-off valve 82 of the two-position three-way valve switches to the left position, and the oil enters the large chamber of the control electro-proportional valve 83 to reduce the displacement of the working variable pump 81 to the minimum displacement. As the current signal increases, the electro-proportional valve 83 controls the displacement of the variable pump 81 to increase from the minimum displacement to the maximum displacement.

[0035] In addressing the issue of high single-action pressure loss in existing multi-way valves with downstream compensating load sensitivity due to the presence of compensators, this embodiment adopts an independent steering and working system scheme. The power source for the independent working system is changed to an electro-proportional variable pump, and the commutation element uses independent valve port control. During single-action (positive load), the valve port is rapidly and fully opened. Through the displacement adjustment of the proportional pump and the speed regulation of the motor, the throttling link is completely eliminated, further reducing the energy consumption of the entire machine's working circuit. In other words: When oil is introduced into the rodless chamber, the inlet and outlet oil valves are opened to the maximum. Volumetric speed regulation is achieved by adjusting the displacement of the electro-proportional pump and adjusting the speed of the motor, thereby reducing pressure loss. When oil is introduced into the rod chamber, the valve stem of the rodless chamber is adjusted to a small opening to generate a certain back pressure, ensuring the stability of the system under heavy load conditions.

[0036] This embodiment uses an electro-proportional valve 83 to control the displacement of the variable pump 81, improving upon existing throttling regulation to flow matching. This allows the output flow of the variable pump 81 to precisely match the required flow of the boom cylinder 94. The structure is simple and compact, eliminating throttling and overflow losses. This not only achieves good energy-saving effects but also improves the smoothness and precision of operation. Furthermore, by eliminating the two main heat sources—throttling and high-pressure overflow—the oil temperature in the hydraulic system is reduced, thereby improving system reliability.

[0037] In this embodiment, see Figure 5 The working module 9 includes a boom control valve 91, a bucket control valve 92, a working overflow valve 93, a boom cylinder 94, and a bucket cylinder 95. The oil outlet of the second pressure matching module 8 is connected to the oil inlet of the boom control valve 91, the oil inlet of the bucket control valve 92, and the working overflow valve 93. The oil outlet of the boom control valve 91 is connected to the boom cylinder 94, and the oil outlet of the bucket control valve 92 is connected to the bucket cylinder 95.

[0038] In this embodiment, the boom control valve 91 includes a first boom solenoid valve E1, a second boom solenoid valve E2, a replenishing oil check valve E3, and a second check valve E4; the oil inlet of the second check valve E4 is connected to the oil outlet of the second pressure matching module 8, and the oil outlet is connected to the oil inlet of the first boom solenoid valve E1 and the second boom solenoid valve E2. The oil outlet of the first boom solenoid valve E1 is connected to the oil inlet Pa of the boom cylinder 94; the oil outlet of the second boom solenoid valve E2 is connected to the oil inlet Pb of the boom cylinder 94. The oil inlet of the replenishing check valve E3 is connected to the oil return ports of the first boom solenoid valve E1 and the second boom solenoid valve E2, and the oil outlet is connected to the oil inlet Pb of the boom cylinder 94. The first boom solenoid valve E1 and the second boom solenoid valve E2 are electrically connected to the main controller 1.

[0039] The working relief valve 93 is used to limit the maximum pressure of the working system. The boom cylinder 94 includes a left boom cylinder 94 and a right boom cylinder 94.

[0040] This embodiment addresses the motion control of the boom cylinder 94 by setting up an independent boom solenoid valve (configured one-to-one with the cylinder). The proportional solenoid valve can receive electrical signals and steplessly adjust the valve core opening, thereby precisely controlling the flow rate into the cylinder and achieving refined and precise hydraulic operation control. The oil replenishment check valve E3 prevents cavitation and air suction, and ensures smooth operation. The second check valve E4 is set as an anti-nodding check valve to firmly lock the oil in the rodless chamber, preventing the boom from falling unexpectedly due to gravity, and ensuring the safety of equipment and personnel.

[0041] In this embodiment, see Figure 6 The bucket control valve 92 includes a first bucket solenoid valve F1, a second bucket solenoid valve F2, a third check valve F3, a first overload replenishing valve F4, and a second overload replenishing valve F5. The oil inlet of the third one-way valve F3 is connected to the oil outlet of the second pressure matching module 8, and the oil outlet is connected to the oil inlet of the first bucket solenoid valve F1 and the second bucket solenoid valve F2. The inlet of the first overload replenishing valve F4 is connected to the outlet of the first bucket solenoid valve F1, and the outlet is connected to the return port; the inlet of the second overload replenishing valve F5 is connected to the outlet of the second bucket solenoid valve F2, and the outlet is connected to the return port. The oil outlet of the first bucket solenoid valve F1 is connected to the oil inlet Pa of the bucket cylinder 95, and the oil outlet of the second bucket solenoid valve F2 is connected to the oil inlet Pb of the bucket cylinder 95.

[0042] The first bucket solenoid valve F1 and the second bucket solenoid valve F2 are electrically connected to the main controller 1.

[0043] In this embodiment, the first bucket solenoid valve F1 and the second bucket solenoid valve F2 are set as independent valve ports for control. By receiving electrical signals, they can precisely control the direction, flow rate, and pressure of the hydraulic oil flowing to the bucket cylinder 95, thereby achieving stepless flow regulation. A third check valve F3 is set as an anti-head-diving check valve to prevent the bucket from automatically sinking, avoiding danger caused by the bucket falling unexpectedly when the equipment is stopped for maintenance or waiting, and effectively improving the safety of bucket operation. A pair of first overload replenishing valves F4 and second overload replenishing valves F5 are set to provide overpressure protection and vacuum replenishing protection for both working chambers of the cylinder.

[0044] In this embodiment, a radiator 96 is also included. The radiator 96 is connected to the oil return port of the boom control valve 91 and the oil return port of the bucket control valve 92, and is also connected to the oil tank 0.

[0045] This embodiment uses a radiator 96 connected to the return port of the boom control valve 91 and the return port of the bucket control valve 92 to cool the oil, thereby effectively preventing the oil from deteriorating at high temperatures and ensuring the reliable and efficient operation of the system.

[0046] In this embodiment, the actuator includes a steering wheel 2 and an operating handle 3 connected to the main controller 1.

[0047] In this embodiment, the steering module 6 includes a left steering cylinder and a right steering cylinder.

[0048] The working principle is as follows: (1) When the whole machine starts without action Both the steering motor 42 and the working motor 72 operate at low speeds. At this time, the replenishing pump 52, which is directly connected to the steering variable pump 51, sets the pressure output flow through the replenishing overflow valve 54 and acts on both ends of the circuit. Most of the oil flows back to the oil tank 0 through the replenishing overflow valve 54, and a small part replenishes the system leakage. The steering variable pump 51 is in a 0 displacement state because it does not receive a steering signal.

[0049] The working variable pump 81 has a minimum displacement (not 0 displacement), at which time it outputs a small flow rate of about 2~3L / min, which generates a standby pressure of about 2~3Mpa at the pump port.

[0050] After the system starts, there is a timer. When a certain set threshold is exceeded (such as no action for 10 seconds), the steering motor 42 and the working motor 72 stop. When the steering wheel 2 or the electric lever is turned, or when the brake or gear signal is detected, the motors (steering motor 42 and working motor 72) are woken up again.

[0051] (2) When turning alone Turning the steering wheel 2 causes the main controller 1 to drive the steering controller 41 to start the steering motor 42, while the working motor 72 maintains a speed of 0.

[0052] At this time, the output flow of the variable steering pump 51 is equal to the speed of the steering motor 42 multiplied by the pump displacement. When the steering wheel 2 speed is slow and less than a certain threshold (e.g., <40 rpm / min), the speed of the steering motor 42 is kept constant, and the displacement of the variable steering pump 51 is adjusted to the maximum first. When the steering wheel 2 speed continues to increase and the steering exceeds the threshold (e.g., ≥40 rpm / min), the maximum displacement of the variable steering pump 51 is kept constant, and the speed of the steering motor 42 is increased until the maximum.

[0053] The specific control method is as follows: when the driver turns the steering wheel 2 to turn (e.g., to the left), the main controller 1 receives the steering signal from the steering wheel 2 and outputs two signals: the first signal controls the displacement of the steering variable pump 51 to increase it; the second signal controls the steering motor 42 to increase its speed. As the driver's steering speed changes, the system outputs flow according to the predetermined control strategy (the above strategy) and enters the left steering cylinder and the right steering cylinder to realize the steering action.

[0054] (3) When the working device moves independently (taking boom lifting as an example) At this time, when the main controller 1 detects no steering signal and no gear or braking signal, it keeps the steering motor 42 in a sleep state; otherwise, it is in a wake-up state. When the driver operates the control handle 3, the main controller 1 receives the handle signal and sends a control signal to the work controller 71. The work controller 71 controls the work motor 72 to rotate and drives the work variable pump 81 to rotate. At the same time, the main controller 1 controls the first boom solenoid valve E1 a1 and the second boom solenoid valve E2 b2 to be energized, so that the first boom solenoid valve E1 works in the left position and the second boom solenoid valve E2 works in the right position, pushing the left boom cylinder 94 and the right boom cylinder 94 to move.

[0055] Similarly to (2), during operation control, the displacement control of the variable pump serves as the primary control method, responsible for setting the flow rate over a wide range with precision. The motor speed control serves as an auxiliary and optimization method, responsible for matching the speed with the load power, performing precise volume control and shock-free adjustment, in order to achieve the ultimate energy-saving effect, noise reduction and stable control.

[0056] (4) When the steering wheel 2 and the pilot handle are operated at the same time, the whole machine turns and the working device moves at the same time. At this time, both the steering wheel 2 and the pilot handle output signals to the main controller 1. After receiving the input signals from the steering wheel 2 and the pilot handle, the main controller 1 controls the movement of the actuator according to the single action program shown in (2) and (3) above.

[0057] This invention, in its embodiment, sets up independently controllable first and second power modules for the steering and normal operation of the loader. Utilizing the coordinated action of a flow scheduling module and a pressure matching module to adapt to independent valve control, it completely eliminates throttling, fully opens the inlet and outlet valves, and minimizes the pressure loss of the oil flowing through the valves, significantly reducing the energy consumption of the entire machine's steering circuit. Simultaneously, through variable speed and displacement speed regulation, it achieves independent and precise control of the oil inlet and outlet of the cylinders, and avoids the constraints of the main valve opening to achieve true stepless speed regulation, thereby greatly improving system energy efficiency.

[0058] The above embodiments are preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the above embodiments. Any changes, modifications, substitutions, combinations, or simplifications made without departing from the spirit and principle of the present invention shall be considered equivalent substitutions and shall be included within the protection scope of the present invention.

Claims

1. A low-power hydraulic system for an electric loader, characterized in that: It includes a main controller and a first power module and a second power module connected to the main controller, as well as a steering module and a working module; The first power module includes a first flow scheduling module and a first pressure matching module. The first flow scheduling module is connected to the main controller and the first pressure matching module. The first pressure matching module is connected to the main controller, the fuel tank, and the steering module. The second power module includes a second flow scheduling module and a second pressure matching module. The second flow scheduling module is connected to the main controller and the second pressure matching module. The second pressure matching module is connected to the main controller, the oil tank, and the working module. The steering module and the working module are controlled by independent valve ports. When the actuator is triggered, the main controller drives the first pressure matching module and / or the second pressure matching module to adjust the displacement to maintain a constant pressure difference, ensuring pressure matching and power response. Then, according to the total flow demand, the main controller controls the first flow scheduling module and / or the second flow scheduling module to smoothly adjust the speed to the target speed, perform flow matching, and perform volumetric speed regulation.

2. The low-power hydraulic system for an electric loader as described in claim 1, characterized in that: The first flow scheduling module includes a steering controller and a steering motor. The steering controller is connected to the main controller and the steering motor, and is used to smoothly adjust the speed of the steering motor to the target speed according to the drive of the main controller when the actuator is triggered to adapt to the total flow demand. The second flow scheduling module includes a working controller and a working motor. The working controller is connected to the main controller and the working motor, and is used to smoothly adjust the speed of the working motor to the target speed according to the drive of the main controller when the actuator is triggered to adapt to the total flow demand.

3. The low-power hydraulic system for an electric loader as described in claim 2, characterized in that: The first pressure matching module includes a steering variable pump, a replenishing pump, a first one-way valve, a replenishing overflow valve, a high-pressure overflow valve, and a flushing valve; the variable pump is mechanically connected to the steering motor and electrically connected to the main controller, its inlet is connected to the replenishing pump and the oil tank, and its outlet is connected to the inlet of the steering module; The inlet of the first check valve is connected to the outlet of the replenishing pump and the replenishing overflow valve, and the outlet is connected to the inlet Pa and inlet Pb of the steering module. The high-pressure overflow valve is connected to the oil inlet and oil tank of the steering module; the flushing valve is connected to the oil inlet and oil tank of the steering module.

4. The low-power hydraulic system for an electric loader as described in claim 2, characterized in that: The second pressure matching module includes a variable displacement pump, a pressure shut-off valve, and an electro-proportional valve, wherein the electro-proportional valve is connected to the variable displacement pump, the pressure shut-off valve, and the main controller; The electro-proportional valve is used to adjust the displacement of the working variable pump according to the drive signal output by the main controller to maintain a constant pressure difference and ensure pressure matching and power response. The variable displacement pump is used to control the electro-proportional valve to reduce the pump's displacement to the minimum displacement when the system pressure exceeds the set pressure value.

5. The low-power hydraulic system for an electric loader as described in claim 1, characterized in that: The working module includes a boom control valve, a bucket control valve, a working relief valve, a boom cylinder, and a bucket cylinder. The oil outlet of the second pressure matching module is connected to the oil inlet of the boom control valve, the oil inlet of the bucket control valve, and the working relief valve. The oil outlet of the boom control valve is connected to the boom cylinder, and the oil outlet of the bucket control valve is connected to the bucket cylinder.

6. The low-power hydraulic system for an electric loader as described in claim 5, characterized in that: The boom control valve includes a first boom solenoid valve, a second boom solenoid valve, a replenishing check valve, and a second check valve; the oil inlet of the second check valve is connected to the oil outlet of the second pressure matching module, and the oil outlet is connected to the oil inlets of the first boom solenoid valve and the second boom solenoid valve. The oil outlet of the first boom solenoid valve is connected to the oil inlet Pa of the boom cylinder; the oil outlet of the second boom solenoid valve is connected to the oil inlet Pb of the boom cylinder. The oil inlet of the replenishing check valve is connected to the oil return port of the first boom solenoid valve and the second boom solenoid valve, and the oil outlet is connected to the oil inlet Pb of the boom cylinder. The first boom solenoid valve and the second boom solenoid valve are electrically connected to the main controller.

7. The low-power hydraulic system of an electric loader as described in claim 5, characterized in that: The bucket control valve includes a first bucket solenoid valve, a second bucket solenoid valve, a third check valve, a first overload replenishing valve, and a second overload replenishing valve. The oil inlet of the third check valve is connected to the oil outlet of the second pressure matching module, and the oil outlet is connected to the oil inlet of the first bucket solenoid valve and the second bucket solenoid valve. The inlet of the first overload replenishing valve is connected to the outlet of the first bucket solenoid valve, and the outlet is connected to the return port; the inlet of the second overload replenishing valve is connected to the outlet of the second bucket solenoid valve, and the outlet is connected to the return port. The oil outlet of the first bucket solenoid valve is connected to the oil inlet Pa of the bucket cylinder, and the oil outlet of the second bucket solenoid valve is connected to the oil inlet Pb of the bucket cylinder. The first bucket solenoid valve and the second bucket solenoid valve are electrically connected to the main controller.

8. The low-power hydraulic system for an electric loader as described in claim 5, characterized in that: It also includes a radiator, which is connected to the oil return port of the boom control valve and the oil return port of the bucket control valve, and is also connected to the oil tank.

9. The low-power hydraulic system for an electric loader as described in claim 1, characterized in that: The actuator includes a steering wheel and a control handle connected to the main controller.

10. The low-power hydraulic system for an electric loader as described in claim 1, characterized in that: The steering module includes a left steering cylinder and a right steering cylinder.

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