A hydraulic system for a loader and an electrically powered loader

Abstract

The utility model relates to the technical field of engineering machinery provides a kind of loader hydraulic system and electric loader, including by the first power source of work pump and first motor, by the second power source of steering pump and second motor, work pump is connected with working hydraulic module, steering pump is connected with braking system, steering hydraulic system. Set up first power source is responsible to working hydraulic module independently, second power source is responsible to braking system and steering hydraulic system simultaneously, on the one hand, using mutually independent first power source, second power source, eliminate the throttling link when traditional steering confluence, reduce the energy consumption of whole machine steering circuit;On the other hand, based on the relativity of braking and steering, share second power source, so as to save one power source, further reduce the cost of whole machine;Set up by the volumetric speed regulation mechanism of " pump + motor " is made, through the variable displacement control of pump and the variable speed control of motor, substantially improve the efficiency of hydraulic circuit, improve the whole machine energy efficiency.

Description

Technical Field

[0001] This utility model relates to the field of engineering machinery technology, and in particular to a hydraulic system for a loader and an electric loader. Background Technology

[0002] A loader is a type of earthmoving machinery widely used in construction projects such as highways, railways, buildings, hydropower, ports, and mines. It is mainly used for loading and unloading bulk materials such as soil, sand, gravel, lime, and coal, and can also perform light digging operations on ores and hard soil. By changing different auxiliary working devices, it can also perform bulldozing, lifting, and loading and unloading operations of other materials such as timber.

[0003] However, current mainstream hydraulic system control schemes still have significant bottlenecks in terms of energy efficiency.

[0004] Firstly, in the widely used quantitative systems and load-sensitive systems combining constant and variable loads, the significant difference in load pressure between the steering and working devices of a loader necessitates a large throttling of the priority valve to ensure steering priority under typical combined steering and working device operation conditions. This results in a substantial throttling pressure loss. This loss directly forces the hydraulic pump outlet pressure to increase, increasing the load on the drive pump motor and causing serious energy waste, leading to persistently high overall machine energy consumption.

[0005] Secondly, the post-valve compensation load-sensing technology used to improve the control performance of multi-way valves also introduces additional throttling pressure loss when the compensator operates alone, which weakens the energy-saving potential of the load-sensing system itself, resulting in the overall energy efficiency advantage of the system not being prominent.

[0006] Furthermore, although existing electric loaders are equipped with adjustable-speed motors and variable displacement pumps, theoretically possessing excellent adjustment flexibility, the speed of the actuators is ultimately determined by the opening degree of the main valve. This control method fails to synergistically leverage the core advantages of continuously variable motor speed control and variable displacement pump displacement adjustment, and the potential for on-demand energy matching in the system is not fully explored, thus hindering further improvements in the overall machine's energy efficiency. Utility Model Content

[0007] This utility model provides a hydraulic system for a loader and an electric loader, which solves the technical problem that the existing hydraulic systems for loaders have high energy consumption due to merging losses and compensation pressure losses.

[0008] To solve the above technical problems, this utility model provides a loader hydraulic system, including: a first power source and a second power source; The first power source includes a working pump and a first motor for driving the working pump; The second power source includes a steering pump and a second motor for driving the steering pump; The oil outlet of the working pump is connected to the working hydraulic module; The oil outlet of the steering pump is connected to the braking system and the steering hydraulic system; When steering or braking, the LS signal fed back from the steering hydraulic system / braking system is acquired to drive the steering pump and / or the second motor to perform volumetric speed regulation and load-sensitive adjustment; during operation, the drive signal from the vehicle controller is acquired to drive the working pump and / or the first motor to perform volumetric speed regulation and flow matching.

[0009] This basic design sets up a first power source that independently powers the working hydraulic module, and a second power source that powers both the braking and steering hydraulic systems. On the one hand, by utilizing the independent first and second power sources, the throttling process during traditional steering convergence is eliminated, reducing the energy consumption of the entire steering circuit. On the other hand, based on the relativity of braking and steering, the second power source is shared, thereby saving energy by using one power source and further reducing the overall cost of the machine. A volumetric speed regulation mechanism consisting of a pump and a motor is set up. Through variable displacement control of the pump and variable speed control of the motor, the efficiency of the hydraulic circuit is greatly improved, enhancing the overall energy efficiency of the machine.

[0010] In a further embodiment, the braking system includes a high-pressure oil filter, a filling valve, a first accumulator, a second accumulator, a third accumulator, a parking brake cylinder, a brake valve, a front axle, and a rear axle; the oil inlet of the high-pressure oil filter is connected to the oil outlet of the steering pump, and the oil outlet is connected to the oil inlet of the filling valve; the oil outlet of the filling valve is connected to the oil inlets of the first accumulator, the second accumulator, the third accumulator, the parking brake cylinder, and the brake valve; and the oil outlet of the brake valve is connected to the front axle and the rear axle.

[0011] This solution connects the filling valve to the outlet of the steering pump via a high-pressure oil filter, allowing the braking system and the steering hydraulic system to share a single power source (steering pump + second motor), eliminating the need for a separate brake pump station and effectively reducing system cost and space requirements. Simultaneously, the integrated high-pressure oil filter effectively filters contaminants from the brake hydraulic fluid, significantly improving the reliability of components such as the brake valves, extending their service life, and ensuring the safe operation of the braking system.

[0012] In a further embodiment, a first shuttle valve is also included, the first shuttle valve having an inlet P1, an inlet P2 and an outlet A, the inlet P1 of the first shuttle valve being connected to the LS port of the steering hydraulic system, the inlet P2 being connected to the S port of the braking system, and the outlet A being connected to the steering pump or the steering hydraulic system.

[0013] This solution sets up a first shuttle valve that connects to both the LS port of the steering hydraulic system and the S port of the braking system, enabling load-sensitive control of the steering pump. By automatically sensing and selecting the highest working pressure in the braking / steering circuit, it feeds back to the load-sensitive port of the steering pump or steering hydraulic system (i.e., the control valve), thereby automatically adjusting the output of the steering pump to provide only the flow and pressure required by the system, further reducing energy loss in single action or standby state.

[0014] In a further embodiment, the steering pump includes a variable displacement pump; When the machine is started without action, the steering pump outputs oil into the braking system, the braking system outputs a braking signal and transmits it to the first shuttle valve through port S, the first shuttle valve transmits it to the steering pump to charge the brake accumulator until the set pressure is reached and maintained; When turning, turning the steering wheel actuates the steering hydraulic system and outputs an LS signal, which is then transmitted to the LS port of the steering pump through the first shuttle valve, driving the steering pump to perform displacement adjustment.

[0015] This solution directly selects a variable displacement pump as the steering pump, and directly transmits the LS signal fed back from the braking / steering circuit to the LS port of the steering pump to drive the steering pump to perform displacement adjustment. This enables precise flow supply output, avoids high pressure overflow and large throttling pressure difference, thereby effectively eliminating throttling losses and achieving significant energy-saving effects.

[0016] In a further embodiment, the first power source further includes a working controller, the input end of which is connected to the vehicle controller and the output end of which is connected to the first motor; the working controller is used to smoothly adjust the speed of the first motor to the target speed according to the drive of the vehicle controller when the actuator is triggered to adapt to the total flow demand. The second power source also includes a steering controller, the input of which is connected to the vehicle controller and the output of which is connected to the second motor; it is used to smoothly adjust the speed of the second motor to the target speed according to the drive of the vehicle controller when the actuator is triggered to meet the total flow demand.

[0017] This solution, based on the original variable displacement adjustment of variable pumps (working pump and steering pump), further realizes variable speed control of steering hydraulic system and working hydraulic system by setting up working controller and steering controller connected to vehicle controller. Since the power source is replaced with electronic control and the throttling link in the circuit is eliminated, the volume adjustment is achieved by variable displacement of variable pump and variable speed of motor, which can significantly reduce the energy consumption of the whole machine.

[0018] In a further embodiment, the steering hydraulic system includes a steering gear, a right steering cylinder, and a left steering cylinder. The oil inlet of the steering gear is connected to the oil outlet of the steering pump, and the oil outlets L and R are respectively connected to the oil inlets of the left steering cylinder and the right steering cylinder.

[0019] In a further embodiment, the steering pump includes a fixed displacement pump; the steering hydraulic system further includes a control valve connected to the vehicle controller, the input end of the control valve being connected to the oil outlet of the steering pump, and its control end being connected to the LS port of the steering gear; The steering pump and the control valve form a metering system. When steering, the steering wheel is turned to drive the steering gear to rotate. The LS signal fed back from the LS port of the steering gear is transmitted to the control valve through the first shuttle valve. The control valve performs the adjustment of the input flow of the steering gear. When braking, the LS signal of the filling valve is transmitted to the control valve through the first shuttle valve to perform filling / cut-off / pressure holding.

[0020] This solution uses a metering pump and control valve to form a metering system. On the one hand, it can adapt to the adaptive adjustment of load-sensitive regulation. On the other hand, the metering pump can continuously provide a stable flow after the engine or motor is started, ensuring the continuity and basic responsiveness of the steering power source and high reliability.

[0021] In a further embodiment, the working hydraulic module includes a distribution valve, a bucket cylinder, and a boom cylinder. The inlet of the distribution valve is connected to the outlet of the working pump, and outlets A and B are respectively connected to the bucket cylinder and the boom cylinder. The control terminal is connected to the vehicle controller.

[0022] In a further embodiment, the system also includes a radiator and a return oil filter. The inlet of the radiator is connected to the return oil port of the working hydraulic module and the return oil port of the steering hydraulic system, and the outlet of the radiator is connected to the inlet of the return oil filter. The outlet of the return oil filter is connected to the oil tank.

[0023] This solution incorporates a radiator at the oil return port, which effectively dissipates heat generated by throttling and friction, maintaining the oil temperature within the optimal operating range. An oil return filter at the oil return port removes contaminants such as wear metal particles and sealing debris generated during operation, thereby directly extending the service life of the entire system.

[0024] This utility model also provides an electric loader, which is equipped with a loader hydraulic system as described above. Attached Figure Description

[0025] Figure 1 This is a perspective view of the overall structure of a loader hydraulic system provided in an embodiment of this utility model; Figure 2 This is provided by the embodiment of the present utility model. Figure 1 Three-dimensional structural diagram of the intermediate and loading production line; Figure 3 This is provided by the embodiment of the present utility model. Figure 2 Three-dimensional structural view of the intermediate clamping mechanism; Among them: First power source A, Second power source B, Working hydraulic module C, Braking system D, Steering hydraulic system E, Vehicle controller F; Working pump 1, first motor 2, steering pump 3, second motor 4; high-pressure oil filter 5, filling valve 6, first accumulator 7, second accumulator 8, third accumulator 9, parking brake cylinder 10, brake valve 11, front axle 12, rear axle 13; first shuttle valve 14; working controller 15, steering controller 16; steering gear 17, right steering cylinder 18, left steering cylinder 19; distribution valve 20, bucket cylinder 21, boom cylinder 22; radiator 23, return oil filter 24; control valve 25. Detailed Implementation

[0026] The embodiments of this utility model 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 utility model. The accompanying drawings are for reference and illustration only and do not constitute a limitation on the scope of patent protection of this utility model, because many changes can be made to this utility model without departing from the spirit and scope of this utility model.

[0027] Example 1 This utility model provides a loader hydraulic system, such as Figure 1 , Figure 2 As shown, in this embodiment, it includes: a first power source A and a second power source B; The first power source A includes a working pump 1 and a first motor 2 for driving the working pump 1; The second power source B includes a steering pump 3 and a second motor 4 for driving the steering pump 3; The oil outlet of the working pump 1 is connected to the working hydraulic module C; The oil outlet of the steering pump 3 is connected to the braking system D and the steering hydraulic system E; When steering or braking, the LS signal fed back from the steering hydraulic system E / the braking system D is acquired to drive the steering pump 3 and / or the second motor 4 to perform volumetric speed regulation and load-sensitive adjustment; when working, the drive signal from the vehicle controller F is acquired to drive the working pump 1 and / or the first motor 2 to perform volumetric speed regulation and flow matching.

[0028] In this embodiment, the braking system D includes a high-pressure oil filter 5, a filling valve 6, a first accumulator 7, a second accumulator 8, a third accumulator 9, a parking brake cylinder 10, a brake valve 11, a front axle 12, and a rear axle 13. The oil inlet of the high-pressure oil filter 5 is connected to the oil outlet of the steering pump 3, and the oil outlet is connected to the oil inlet of the filling valve 6. The oil outlet of the filling valve 6 is connected to the oil inlets of the first accumulator 7, the second accumulator 8, the third accumulator 9, the parking brake cylinder 10, and the brake valve 11. The oil outlets A1 and A2 of the brake valve 11 are respectively connected to the front axle 12 and the rear axle 13.

[0029] The oil outlets A1, A2, and A3 of the high-pressure oil filter 5 are connected to the oil inlet P1 of the brake valve 11, the second accumulator 8, and the third accumulator 9, respectively, and the oil outlets B1, B2, and B3 are connected to the first accumulator 7, the oil inlet P2 of the brake valve 11, and the parking brake cylinder 10, respectively.

[0030] In this embodiment, the filling valve 6 is connected to the outlet of the steering pump 3 via the high-pressure oil filter 5, so that the braking system D and the steering hydraulic system E are driven by a single power source (steering pump 3 + second motor 4), eliminating the need for a separate brake pump station and effectively reducing system cost and space occupation. At the same time, the integrated high-pressure oil filter 5 can effectively filter contaminants in the brake hydraulic oil, significantly improving the reliability of components such as the brake valve 11, extending their service life, and ensuring the safe operation of the braking system D.

[0031] In this embodiment, a first shuttle valve 14 is also included. The first shuttle valve 14 includes an oil inlet P1, an oil inlet P2, and an oil outlet A. The oil inlet P1 of the first shuttle valve 14 is connected to the LS port of the steering hydraulic system E, the oil inlet P2 is connected to the S port of the braking system D, and the oil outlet A is connected to the steering pump 3.

[0032] In this embodiment, the first shuttle valve 14 is connected to both the LS port of the steering hydraulic system E and the S port of the braking system D to achieve load-sensitive control of the steering pump 3. By automatically sensing and selecting the highest working pressure in the braking / steering circuit, it feeds it back to the load-sensitive port of the steering pump 3, thereby automatically adjusting the output of the steering pump 3 to provide only the flow and pressure required by the system, further reducing energy loss in single action or standby state.

[0033] In this embodiment, the steering pump 3 includes a variable displacement pump; When the machine is started without action, the steering pump 3 outputs oil into the braking system D, the braking system D outputs a braking signal and transmits it to the first shuttle valve 14 through port S, and the first shuttle valve 14 transmits it to the steering pump 3 to charge the brake accumulator until the set pressure is reached and maintained. When turning, the steering wheel is turned to activate the steering hydraulic system E and output an LS signal, which is then transmitted to the LS port of the steering pump 3 through the first shuttle valve 14, driving the steering pump 3 to perform displacement adjustment.

[0034] In this embodiment, a variable displacement pump is directly selected as the steering pump 3. The LS signal fed back from the braking / steering circuit is directly transmitted to the LS port of the steering pump 3 to drive the steering pump 3 to perform displacement adjustment. This can achieve precise flow supply output, avoid high pressure overflow and large throttling pressure difference, thereby effectively eliminating throttling loss and achieving significant energy saving effect.

[0035] In this embodiment, the first power source A further includes a working controller 15. The input end of the working controller 15 is connected to the vehicle controller F, and the output end is connected to the first motor 2. The working controller 15 is used to smoothly adjust the speed of the first motor 2 to the target speed according to the drive of the vehicle controller F when the actuator is triggered to adapt to the total flow demand. The second power source B also includes a steering controller 16, the input end of which is connected to the vehicle controller F and the output end of which is connected to the second motor 4; it is used to smoothly adjust the speed of the second motor 4 to the target speed according to the drive of the vehicle controller F when the actuator is triggered to meet the total flow demand.

[0036] The actuator includes a steering wheel, a brake pedal, and an operating handle (electric handle) connected to the vehicle controller F. Thus, the steering hydraulic system E is activated and maintained at a fixed speed via the brake pedal angle signal; the operating handle inputs signals to the vehicle controller F and outputs signals to the work controller 15, the variable displacement pump 1, and the distribution valve 20 to achieve speed regulation.

[0037] Based on the original variable displacement adjustment of the variable pumps (working pump 1 and steering pump 3), this embodiment further realizes variable speed control of the steering hydraulic system E and the working hydraulic system by setting up a working controller 15 and a steering controller 16 connected to the vehicle controller F. Since the power source is replaced with an electronic control method and the throttling link in the circuit is eliminated, the volume adjustment is achieved by changing the displacement of the variable pump and the speed of the motor, which can significantly reduce the energy consumption of the whole machine.

[0038] In this embodiment, the steering hydraulic system E includes a steering gear 17, a right steering cylinder 18, and a left steering cylinder 19. The oil inlet of the steering gear 17 is connected to the oil outlet of the steering pump 3, and the oil outlets L and R are connected to the oil inlets of the left steering cylinder 19 and the right steering cylinder 18, respectively.

[0039] Meanwhile, the steering gear 17 adopts an independent valve port control form, which makes the valve port open quickly and fully when in single action (positive load). Through the displacement adjustment of the proportional pump (steering pump 3) and the speed adjustment of the second motor 4, the throttling link in the original working system is completely eliminated, further reducing the energy consumption of the whole machine working circuit.

[0040] Because the steering hydraulic system E and the braking system D share a common power source, when steering, the steering wheel is turned to rotate the steering gear 17, and the first shuttle valve 14 transmits the LS signal transmitted by the steering gear 17 to the variable pump. The steering pump 3 and the second motor 4 work together to adjust and match the flow rate. When braking, the LS signal of the filling valve 6 is transmitted to the variable pump through the first shuttle valve 14 to realize the functions of filling, cutting off and maintaining pressure.

[0041] In this embodiment, the working hydraulic module C includes a distribution valve 20, a bucket cylinder 21, and a boom cylinder 22. The oil inlet of the distribution valve 20 is connected to the oil outlet of the working pump 1, and the oil outlets A and B are respectively connected to the bucket cylinder 21 and the boom cylinder 22. The control terminal is connected to the vehicle controller F.

[0042] Among them, the working pump 1 is preferably an electro-proportional variable pump.

[0043] The distribution valve 20 is preferably an electrically controlled open-center multi-way valve. When an electrical signal is detected in the pilot valve, the valve stem is moved. Volumetric speed regulation is achieved through the displacement adjustment of the electric proportional pump (working pump 1) and the variable speed adjustment of the motor (first motor 2), allowing the working device to move according to the driver's intention. The oil output from the steering pump 3 is supplied to the pilot valve of the distribution valve 20 through a small-diameter pipe at a low flow rate.

[0044] In this embodiment, a radiator 23 and a return oil filter 24 are also included. The oil inlet of the radiator 23 is connected to the return oil port of the working hydraulic module C and the return oil port of the steering hydraulic system E, and the oil outlet is connected to the oil inlet of the return oil filter 24. The oil outlet of the return oil filter 24 is connected to the oil tank.

[0045] In this embodiment, a radiator 23 is installed at the oil return port, which can effectively dissipate the heat generated by the system due to throttling and friction, and maintain the oil temperature within the optimal operating range. An oil return filter 24 is installed at the oil return port to filter out contaminants such as wear metal particles and sealing debris generated by the operation of the oil, thereby directly extending the service life of the entire system.

[0046] The working principle of this embodiment is as follows: (1) When the machine is started without operation, both the first motor 2 and the second motor 4 run at the set standby speed. At this time, the accumulators (first accumulator 7, second accumulator 8, and third accumulator 9) in the braking system D are empty cavities. The oil output from the steering pump 3 enters the accumulator to fill it. At the same time, the filling valve 6S port outputs a braking signal and transmits it from the S port to the LS port of the steering pump 3 through the first shuttle valve 14, forming a closed-loop feedback. The steering pump 3 starts to fill the brake accumulator until the set pressure is reached. The filling valve 6S port releases pressure, and the steering pump 3 maintains the standby pressure state. The working pump 12 has a minimum displacement (not 0 displacement). At this time, it outputs a small flow rate of about 2~3L / min, which generates a standby pressure of about 0.5Mpa at the pump port.

[0047] After the liquid filling is completed, the system is set with a timer. When a certain set threshold is exceeded (such as no action for 10 seconds), the first motor 2 and the second motor 4 stop. When any signal such as the electric handle is turned on, the brake pedal is pressed, the brake accumulator pressure is low, or the gear position signal is received, the first motor 2 and the second motor 4 are woken up again.

[0048] (2) When steering alone, only the second motor 4 and the steering pump 3 work, and the speed of the first motor 2 remains at 0. When the second motor 4 stops, the driver lightly presses the brake pedal to wake up the second motor 4 and keep it at the set standby speed. The steering wheel is turned to drive the steering gear 17 to turn. The steering gear 17 outputs the LS signal and transmits it to the LS port of the steering pump 3 through the S1 port and S port of the first shuttle valve 14 in sequence. At this time, the steering pump 3, as a variable pump, adjusts the displacement to meet the flow required for steering. The flow output of the steering gear 17 enters the right steering cylinder 18 or the left steering cylinder 19 to realize the steering action.

[0049] (3) When the working device moves independently (taking boom lifting as an example), the steering motor detects the electric handle signal and remains in the standby wake-up state. When the driver operates the electric handle (operating handle), the vehicle controller F receives the handle signal and then sends a control signal to the working controller 15. The working controller 15 controls the first motor 2 to rotate and drives the working pump 1 to rotate; at the same time, the controller controls the solenoid valves a1 and b1 in the distribution valve 20 to be energized, so that the boom valve rod of the distribution valve 20 changes direction, pushing the boom cylinder 22 to move.

[0050] The specific control strategy is to only control the valve opening to increase in the first half of the handle, while keeping the motor speed constant; when the valve stem is opened to the maximum, the motor speed is increased to maximize the system's energy efficiency.

[0051] Example 2 This utility model provides a loader hydraulic system, such as Figure 3 As shown, the difference between this embodiment and Embodiment 1 is that: In this embodiment, the steering pump 3 includes a fixed displacement pump; the steering hydraulic system E also includes a control valve 25 connected to the vehicle controller F. The input end of the control valve 25 is connected to the oil outlet of the steering pump 3, and its control end is connected to the LS port of the steering gear 17, for load-sensitive adjustment and maximum pressure limit of the fixed displacement pump. In this embodiment, the first shuttle valve 14 includes an oil inlet P1, an oil inlet P2, and an oil outlet A. The oil inlet P1 of the first shuttle valve 14 is connected to the LS port of the steering hydraulic system E, the oil inlet P2 is connected to the S port of the braking system D, and the oil outlet A is connected to the control valve 25.

[0052] The steering pump 3 and the control valve 25 form a metering system. When steering, the steering wheel is turned to drive the steering gear 17 to rotate. The LS signal fed back from the LS port of the steering gear 17 is transmitted to the control valve 25 through the first shuttle valve 14. The control valve 25 performs the adjustment of the input flow of the steering gear 17. When braking, the LS signal of the filling valve 6 is transmitted to the control valve 25 through the first shuttle valve 14 to perform filling / cut-off / pressure holding.

[0053] In this embodiment, a metering pump and control valve 25 are set up to form a metering system. On the one hand, it can adapt to the adaptive adjustment of load-sensitive adjustment. On the other hand, the metering pump can continuously provide a stable flow after the engine or motor is started, ensuring the continuity and basic responsiveness of the steering power source and high reliability.

[0054] Taking the steering pump 3 as a fixed displacement pump and the working pump 1 as a variable displacement pump as an example, the working principle of this embodiment is as follows: (1) When the whole machine is started without action, the first motor 2 and the second motor 4 are both running at the set standby speed. At this time, the accumulator in the braking system D is an empty cavity. The metering pump (steering pump 3) has oil entering the accumulator to charge it. At the same time, the charging valve 6S port outputs a braking signal and transmits it to the control valve 25 through the S port of the first shuttle valve 14. The metering pump starts to charge the brake accumulator until the set pressure is reached. The charging valve 6S port releases pressure and the metering pump maintains the standby pressure state set by the control valve 25. The working pump 1 has a minimum displacement (not 0 displacement). At this time, it outputs a small flow rate of about 2~3L / min to generate a standby pressure of about 0.5Mpa at the pump port.

[0055] After the liquid filling is completed, the system is set with a timer. When a certain set threshold is exceeded (such as no action for 10 seconds), the first motor 2 and the second motor 4 stop. When any signal such as the electric handle is turned on, the brake pedal is pressed, the brake accumulator pressure is low, or the gear signal is received, the steering and working motors are reactivated.

[0056] (2) When steering alone, only the second motor 4 and the steering pump 3 work, and the speed of the first motor 2 remains at 0. When the motor stops, the driver lightly presses the brake pedal to wake up the second motor 4 and keep it at the set standby speed; turning the steering wheel drives the steering gear 17 to turn, and the steering gear 17 outputs an LS signal, which is transmitted to the LS port of the control valve 25 through the S1 port and S port of the first shuttle valve 14. The fixed displacement pump outputs flow to meet the flow required for steering, and the flow output of the steering gear 17 enters the right steering cylinder 18 or the left steering cylinder 19 to realize the steering action. Excess flow from the fixed displacement pump returns part of it to the oil tank from the left position of the control valve 25; (3) When the working device moves independently (taking boom lifting as an example), the second motor 4 detects the electric handle (operating handle) signal and always remains in the standby wake-up state. When the driver operates the electric handle, the vehicle controller F receives the handle signal and then sends a control signal to the working controller 15. The working controller 15 controls the first motor 2 to rotate and drives the working pump 1 to rotate; at the same time, the vehicle controller F controls the solenoid valves a1 and b1 to be energized, so that the boom valve rod of the distribution valve 20 is reversed, pushing the boom cylinder 22 to move.

[0057] The specific control strategy is to only control the valve opening to increase in the first half of the handle, while keeping the motor speed constant; when the valve stem is opened to the maximum, the motor speed is increased to maximize the system's energy efficiency.

[0058] Example 3 This utility model embodiment also provides an electric loader, which is equipped with a loader hydraulic system as described in embodiment 1 or 2 above.

[0059] This utility model features a first power source A independently supplying power to the working hydraulic module C, and a second power source B simultaneously supplying power to the braking system D and the steering hydraulic system E. On one hand, by utilizing the independent first power source A and second power source B, the throttling process during traditional steering convergence is eliminated, reducing the energy consumption of the entire steering circuit. On the other hand, based on the relativity of braking and steering, the second power source B is shared, thereby saving energy by eliminating one power source and further reducing the overall cost. A volumetric speed regulation mechanism consisting of a pump and a motor is incorporated, significantly improving the efficiency of the hydraulic circuit and enhancing the overall energy efficiency through variable pump displacement control and variable motor speed control.

[0060] The above embodiments are preferred embodiments of the present utility model, but the embodiments of the present utility model 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 utility model shall be considered equivalent substitutions and shall be included within the protection scope of the present utility model.

Claims

1. A hydraulic system for a loader, characterized in that, include: First power source, second power source; The first power source includes a working pump and a first motor for driving the working pump; The second power source includes a steering pump and a second motor for driving the steering pump; The oil outlet of the working pump is connected to the working hydraulic module; The oil outlet of the steering pump is connected to the braking system and the steering hydraulic system; When steering or braking, the LS signal fed back from the steering hydraulic system / braking system is acquired to drive the steering pump and / or the second motor to perform volumetric speed regulation and load-sensitive adjustment; during operation, the drive signal from the vehicle controller is acquired to drive the working pump and / or the first motor to perform volumetric speed regulation and flow matching.

2. The loader hydraulic system as described in claim 1, characterized in that: The braking system includes a high-pressure oil filter, a filling valve, a first accumulator, a second accumulator, a third accumulator, a parking brake cylinder, a brake valve, a front axle, and a rear axle. The oil inlet of the high-pressure oil filter is connected to the oil outlet of the steering pump, and the oil outlet is connected to the oil inlet of the filling valve. The oil outlet of the filling valve is connected to the oil inlets of the first accumulator, the second accumulator, the third accumulator, the parking brake cylinder, and the brake valve. The oil outlet of the brake valve is connected to the front axle and the rear axle.

3. The loader hydraulic system as described in claim 2, characterized in that: It also includes a first shuttle valve, which includes an oil inlet P1, an oil inlet P2, and an oil outlet A. The oil inlet P1 of the first shuttle valve is connected to the LS port of the steering hydraulic system, the oil inlet P2 is connected to the S port of the braking system, and the oil outlet A is connected to the steering pump or the steering hydraulic system.

4. A loader hydraulic system as described in claim 3, characterized in that: The steering pump includes a variable displacement pump; When the machine is started without action, the steering pump outputs oil into the braking system, the braking system outputs a braking signal and transmits it to the first shuttle valve through port S, the first shuttle valve transmits it to the steering pump to charge the brake accumulator until the set pressure is reached and maintained; When turning, turning the steering wheel actuates the steering hydraulic system and outputs an LS signal, which is then transmitted to the LS port of the steering pump through the first shuttle valve, driving the steering pump to perform displacement adjustment.

5. A loader hydraulic system as described in claim 1, characterized in that: The first power source also includes a working controller, the input end of which is connected to the vehicle controller and the output end of which is connected to the first motor. The working controller is used to smoothly adjust the speed of the first motor to the target speed according to the drive of the vehicle controller when the actuator is triggered to meet the total flow demand. The second power source also includes a steering controller, the input of which is connected to the vehicle controller and the output of which is connected to the second motor; When the actuator is triggered, the second motor is smoothly adjusted to the target speed according to the drive of the vehicle controller to meet the total flow demand.

6. A loader hydraulic system as described in claim 3, characterized in that: The steering hydraulic system includes a steering gear, a right steering cylinder, and a left steering cylinder. The oil inlet of the steering gear is connected to the oil outlet of the steering pump, and the oil outlets L and R are connected to the oil inlets of the left steering cylinder and the right steering cylinder, respectively.

7. A loader hydraulic system as described in claim 6, characterized in that: The steering pump includes a fixed displacement pump; the steering hydraulic system also includes a control valve connected to the vehicle controller, the input end of the control valve being connected to the oil outlet of the steering pump, and its control end being connected to the LS port of the steering gear. The steering pump and the control valve form a metering system. When steering, the steering wheel is turned to drive the steering gear to rotate. The LS signal fed back from the LS port of the steering gear is transmitted to the control valve through the first shuttle valve. The control valve performs the adjustment of the input flow of the steering gear. When braking, the LS signal of the filling valve is transmitted to the control valve through the first shuttle valve to perform filling / cut-off / pressure holding.

8. A loader hydraulic system as described in claim 1, characterized in that: The working hydraulic module includes a distribution valve, a bucket cylinder, and a boom cylinder. The oil inlet of the distribution valve is connected to the oil outlet of the working pump. Oil outlet A and oil outlet B are respectively connected to the bucket cylinder and the boom cylinder. The control terminal is connected to the vehicle controller.

9. A loader hydraulic system as described in claim 1, characterized in that: It also includes a radiator and a return oil filter. The oil inlet of the radiator is connected to the return oil port of the working hydraulic module and the return oil port of the steering hydraulic system, and the oil outlet is connected to the oil inlet of the return oil filter. The oil outlet of the return oil filter is connected to the oil tank.

10. An electric loader, characterized in that: The electric loader is equipped with a loader hydraulic system as described in any one of claims 1 to 9.

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